diff --git a/backend/Gemfile b/backend/Gemfile
index 1d48493..2d0a90c 100644
--- a/backend/Gemfile
+++ b/backend/Gemfile
@@ -50,8 +50,6 @@ group :development, :test do
   gem 'factory_bot_rails'
 end
 
-
-
 gem "mysql2", "~> 0.5.6"
 
 gem "image_processing", "~> 1.14"
@@ -69,3 +67,5 @@ gem 'whenever', require: false
 gem 'discard'
 
 gem "rspec-rails", "~> 8.0", :groups => [:development, :test]
+
+gem 'aws-sdk-s3', require: false
diff --git a/backend/Gemfile.lock b/backend/Gemfile.lock
index 42eb862..f9dc02c 100644
--- a/backend/Gemfile.lock
+++ b/backend/Gemfile.lock
@@ -73,6 +73,25 @@ GEM
       tzinfo (~> 2.0, >= 2.0.5)
       uri (>= 0.13.1)
     ast (2.4.3)
+    aws-eventstream (1.4.0)
+    aws-partitions (1.1231.0)
+    aws-sdk-core (3.244.0)
+      aws-eventstream (~> 1, >= 1.3.0)
+      aws-partitions (~> 1, >= 1.992.0)
+      aws-sigv4 (~> 1.9)
+      base64
+      bigdecimal
+      jmespath (~> 1, >= 1.6.1)
+      logger
+    aws-sdk-kms (1.123.0)
+      aws-sdk-core (~> 3, >= 3.244.0)
+      aws-sigv4 (~> 1.5)
+    aws-sdk-s3 (1.217.0)
+      aws-sdk-core (~> 3, >= 3.244.0)
+      aws-sdk-kms (~> 1)
+      aws-sigv4 (~> 1.5)
+    aws-sigv4 (1.12.1)
+      aws-eventstream (~> 1, >= 1.0.2)
     base64 (0.2.0)
     bcrypt_pbkdf (1.1.1)
     bcrypt_pbkdf (1.1.1-arm64-darwin)
@@ -157,6 +176,7 @@ GEM
       pp (>= 0.6.0)
       rdoc (>= 4.0.0)
       reline (>= 0.4.2)
+    jmespath (1.6.2)
     json (2.12.0)
     jwt (2.10.1)
       base64
@@ -441,6 +461,7 @@ PLATFORMS
   x86_64-linux-musl
 
 DEPENDENCIES
+  aws-sdk-s3
   bootsnap
   brakeman
   diff-lcs
diff --git a/backend/app/controllers/materials_controller.rb b/backend/app/controllers/materials_controller.rb
new file mode 100644
index 0000000..fd5e9b8
--- /dev/null
+++ b/backend/app/controllers/materials_controller.rb
@@ -0,0 +1,94 @@
+class MaterialsController < ApplicationController
+  def index
+    page = (params[:page].presence || 1).to_i
+    limit = (params[:limit].presence || 20).to_i
+
+    page = 1 if page < 1
+    limit = 1 if limit < 1
+
+    offset = (page - 1) * limit
+
+    tag_id = params[:tag_id].presence
+    parent_id = params[:parent_id].presence
+
+    q = Material.includes(:tag, :created_by_user).with_attached_file
+    q = q.where(tag_id:) if tag_id
+    q = q.where(parent_id:) if parent_id
+
+    count = q.count
+    materials = q.order(created_at: :desc, id: :desc).limit(limit).offset(offset)
+
+    render json: { materials: materials.map { |m| material_json(m) }, count: count }
+  end
+
+  def show
+    material = Material.includes(:tag, :created_by_user).with_attached_file.find_by(id: params[:id])
+    return head :not_found unless material
+
+    render json: material_json(material)
+  end
+
+  def create
+    return head :unauthorized unless current_user
+    return head :forbidden unless current_user.gte_member?
+
+    file = params[:file]
+    return head :bad_request if file.blank?
+
+    material = Material.new(
+        url: params[:url].presence,
+        parent_id: params[:parent_id].presence,
+        tag_id: params[:tag_id].presence,
+        created_by_user: current_user)
+    material.file.attach(file)
+
+    if material.save
+      render json: material_json(material), status: :created
+    else
+      render json: { errors: material.errors.full_messages }, status: :unprocessable_entity
+    end
+  end
+
+  def update
+    return head :unauthorized unless current_user
+    return head :forbidden unless current_user.gte_member?
+
+    material = Material.with_attached_file.find_by(id: params[:id])
+    return head :not_found unless material
+
+    material.assign_attributes(
+      url: params[:url].presence,
+      parent_id: params[:parent_id].presence,
+      tag_id: params[:tag_id].presence
+    )
+    material.file.attach(params[:file]) if params[:file].present?
+
+    if material.save
+      render json: material_json(material)
+    else
+      render json: { errors: material.errors.full_messages }, status: :unprocessable_entity
+    end
+  end
+
+  def destroy
+    return head :unauthorized unless current_user
+    return head :forbidden unless current_user.gte_member?
+
+    material = Material.find_by(id: params[:id])
+    return head :not_found unless material
+
+    material.discard
+    head :no_content
+  end
+
+  private
+
+  def material_json(material)
+    MaterialRepr.base(material).merge(
+      'filename' => material.file.attached? ? material.file.filename.to_s : nil,
+      'byte_size' => material.file.attached? ? material.file.byte_size : nil,
+      'content_type' => material.file.attached? ? material.file.content_type : nil,
+      'url' => material.file.attached? ? url_for(material.file) : nil
+    )
+  end
+end
diff --git a/backend/app/models/material.rb b/backend/app/models/material.rb
new file mode 100644
index 0000000..37af665
--- /dev/null
+++ b/backend/app/models/material.rb
@@ -0,0 +1,31 @@
+class Material < ApplicationRecord
+  include MyDiscard
+
+  default_scope -> { kept }
+
+  belongs_to :parent, class_name: 'Material', optional: true
+  has_many :children, class_name: 'Material', foreign_key: :parent_id, dependent: :nullify
+
+  belongs_to :tag, optional: true
+  belongs_to :created_by_user, class_name: 'User', optional: true
+  belongs_to :updated_by_user, class_name: 'User', optional: true
+
+  has_one_attached :file, dependent: :purge
+
+  validate :file_must_be_attached
+  validate :tag_must_be_material_category
+
+  private
+
+  def file_must_be_attached
+    return if url.present? || file.attached?
+
+    errors.add(:url, 'URL かファイルのどちらかは必須です．')
+  end
+
+  def tag_must_be_material_category
+    return if tag.blank? || tag.material?
+
+    errors.add(:tag, '素材カテゴリのタグを指定してください．')
+  end
+end
diff --git a/backend/app/representations/material_repr.rb b/backend/app/representations/material_repr.rb
new file mode 100644
index 0000000..ed76450
--- /dev/null
+++ b/backend/app/representations/material_repr.rb
@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+
+
+module MaterialRepr
+  BASE = { only: [:id, :url, :parent_id, :created_at, :updated_at],
+           include: { created_by_user: UserRepr::BASE, tag: TagRepr::BASE } }.freeze
+
+  module_function
+
+  def base(material)
+    material.as_json(BASE)
+  end
+
+  def many(materials)
+    materials.map { |m| base(m) }
+  end
+end
diff --git a/backend/config/environments/production.rb b/backend/config/environments/production.rb
index 0bd58c3..8477b2d 100644
--- a/backend/config/environments/production.rb
+++ b/backend/config/environments/production.rb
@@ -19,7 +19,7 @@ Rails.application.configure do
   # config.asset_host = "http://assets.example.com"
 
   # Store uploaded files on the local file system (see config/storage.yml for options).
-  config.active_storage.service = :local
+  config.active_storage.service = :r2
 
   # Assume all access to the app is happening through a SSL-terminating reverse proxy.
   config.assume_ssl = true
diff --git a/backend/config/routes.rb b/backend/config/routes.rb
index b9db110..e2d098b 100644
--- a/backend/config/routes.rb
+++ b/backend/config/routes.rb
@@ -81,4 +81,6 @@ Rails.application.routes.draw do
 
     resources :comments, controller: :theatre_comments, only: [:index, :create]
   end
+
+  resources :materials, only: [:index, :show, :create, :update, :destroy]
 end
diff --git a/backend/config/storage.yml b/backend/config/storage.yml
index 4942ab6..c2c2a46 100644
--- a/backend/config/storage.yml
+++ b/backend/config/storage.yml
@@ -6,29 +6,10 @@ local:
   service: Disk
   root: <%= Rails.root.join("storage") %>
 
-# Use bin/rails credentials:edit to set the AWS secrets (as aws:access_key_id|secret_access_key)
-# amazon:
-#   service: S3
-#   access_key_id: <%= Rails.application.credentials.dig(:aws, :access_key_id) %>
-#   secret_access_key: <%= Rails.application.credentials.dig(:aws, :secret_access_key) %>
-#   region: us-east-1
-#   bucket: your_own_bucket-<%= Rails.env %>
-
-# Remember not to checkin your GCS keyfile to a repository
-# google:
-#   service: GCS
-#   project: your_project
-#   credentials: <%= Rails.root.join("path/to/gcs.keyfile") %>
-#   bucket: your_own_bucket-<%= Rails.env %>
-
-# Use bin/rails credentials:edit to set the Azure Storage secret (as azure_storage:storage_access_key)
-# microsoft:
-#   service: AzureStorage
-#   storage_account_name: your_account_name
-#   storage_access_key: <%= Rails.application.credentials.dig(:azure_storage, :storage_access_key) %>
-#   container: your_container_name-<%= Rails.env %>
-
-# mirror:
-#   service: Mirror
-#   primary: local
-#   mirrors: [ amazon, google, microsoft ]
+r2:
+  service: S3
+  endpoint: <%= ENV['R2_ENDPOINT'] %>
+  access_key_id: <%= ENV['R2_ACCESS_KEY_ID'] %>
+  secret_access_key: <%= ENV['R2_SECRET_ACCESS_KEY'] %>
+  bucket: <%= ENV['R2_BUCKET'] %>
+  region: auto
diff --git a/backend/db/migrate/20260329034700_create_materials.rb b/backend/db/migrate/20260329034700_create_materials.rb
new file mode 100644
index 0000000..ecb1c07
--- /dev/null
+++ b/backend/db/migrate/20260329034700_create_materials.rb
@@ -0,0 +1,34 @@
+class CreateMaterials < ActiveRecord::Migration[8.0]
+  def change
+    create_table :materials do |t|
+      t.string :url
+      t.references :parent, index: true, foreign_key: { to_table: :materials }
+      t.references :tag, index: true, foreign_key: true
+      t.references :created_by_user, foreign_key: { to_table: :users }
+      t.references :updated_by_user, foreign_key: { to_table: :users }
+      t.timestamps
+      t.datetime :discarded_at, index: true
+      t.virtual :active_url, type: :string,
+                             as: 'IF(discarded_at IS NULL, url, NULL)',
+                             stored: false
+
+      t.index :active_url, unique: true
+    end
+
+    create_table :material_versions do |t|
+      t.references :material, null: false, foreign_key: true
+      t.integer :version_no, null: false
+      t.string :url, index: true
+      t.references :parent, index: true, foreign_key: { to_table: :materials }
+      t.references :tag, index: true, foreign_key: true
+      t.references :created_by_user, foreign_key: { to_table: :users }
+      t.references :updated_by_user, foreign_key: { to_table: :users }
+      t.timestamps
+      t.datetime :discarded_at, index: true
+
+      t.index [:material_id, :version_no],
+              unique: true,
+              name: 'index_material_versions_on_material_id_and_version_no'
+    end
+  end
+end
diff --git a/backend/db/schema.rb b/backend/db/schema.rb
index 6a2096b..22541e2 100644
--- a/backend/db/schema.rb
+++ b/backend/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.0].define(version: 2026_03_17_015000) do
+ActiveRecord::Schema[8.0].define(version: 2026_03_29_034700) do
   create_table "active_storage_attachments", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "name", null: false
     t.string "record_type", null: false
@@ -56,6 +56,45 @@ ActiveRecord::Schema[8.0].define(version: 2026_03_17_015000) do
     t.index ["ip_address"], name: "index_ip_addresses_on_ip_address", unique: true
   end
 
+  create_table "material_versions", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.bigint "material_id", null: false
+    t.integer "version_no", null: false
+    t.string "url"
+    t.bigint "parent_id"
+    t.bigint "tag_id"
+    t.bigint "created_by_user_id"
+    t.bigint "updated_by_user_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.datetime "discarded_at"
+    t.index ["created_by_user_id"], name: "index_material_versions_on_created_by_user_id"
+    t.index ["discarded_at"], name: "index_material_versions_on_discarded_at"
+    t.index ["material_id", "version_no"], name: "index_material_versions_on_material_id_and_version_no", unique: true
+    t.index ["material_id"], name: "index_material_versions_on_material_id"
+    t.index ["parent_id"], name: "index_material_versions_on_parent_id"
+    t.index ["tag_id"], name: "index_material_versions_on_tag_id"
+    t.index ["updated_by_user_id"], name: "index_material_versions_on_updated_by_user_id"
+    t.index ["url"], name: "index_material_versions_on_url"
+  end
+
+  create_table "materials", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.string "url"
+    t.bigint "parent_id"
+    t.bigint "tag_id"
+    t.bigint "created_by_user_id"
+    t.bigint "updated_by_user_id"
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.datetime "discarded_at"
+    t.virtual "active_url", type: :string, as: "if((`discarded_at` is null),`url`,NULL)"
+    t.index ["active_url"], name: "index_materials_on_active_url", unique: true
+    t.index ["created_by_user_id"], name: "index_materials_on_created_by_user_id"
+    t.index ["discarded_at"], name: "index_materials_on_discarded_at"
+    t.index ["parent_id"], name: "index_materials_on_parent_id"
+    t.index ["tag_id"], name: "index_materials_on_tag_id"
+    t.index ["updated_by_user_id"], name: "index_materials_on_updated_by_user_id"
+  end
+
   create_table "nico_tag_relations", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.bigint "nico_tag_id", null: false
     t.bigint "tag_id", null: false
@@ -239,6 +278,19 @@ ActiveRecord::Schema[8.0].define(version: 2026_03_17_015000) do
     t.datetime "updated_at", null: false
   end
 
+  create_table "wiki_assets", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
+    t.bigint "wiki_page_id", null: false
+    t.integer "no", null: false
+    t.string "alt_text"
+    t.binary "sha256", limit: 32, null: false
+    t.bigint "created_by_user_id", null: false
+    t.datetime "created_at", null: false
+    t.datetime "updated_at", null: false
+    t.index ["created_by_user_id"], name: "index_wiki_assets_on_created_by_user_id"
+    t.index ["wiki_page_id", "no"], name: "index_wiki_assets_on_wiki_page_id_and_no", unique: true
+    t.index ["wiki_page_id", "sha256"], name: "index_wiki_assets_on_wiki_page_id_and_sha256", unique: true
+  end
+
   create_table "wiki_lines", charset: "utf8mb4", collation: "utf8mb4_0900_ai_ci", force: :cascade do |t|
     t.string "sha256", limit: 64, null: false
     t.text "body", null: false
@@ -254,6 +306,7 @@ ActiveRecord::Schema[8.0].define(version: 2026_03_17_015000) do
     t.datetime "created_at", null: false
     t.datetime "updated_at", null: false
     t.datetime "discarded_at"
+    t.integer "next_asset_no", default: 1, null: false
     t.index ["created_user_id"], name: "index_wiki_pages_on_created_user_id"
     t.index ["discarded_at"], name: "index_wiki_pages_on_discarded_at"
     t.index ["tag_name_id"], name: "index_wiki_pages_on_tag_name_id", unique: true
@@ -292,6 +345,15 @@ ActiveRecord::Schema[8.0].define(version: 2026_03_17_015000) do
 
   add_foreign_key "active_storage_attachments", "active_storage_blobs", column: "blob_id"
   add_foreign_key "active_storage_variant_records", "active_storage_blobs", column: "blob_id"
+  add_foreign_key "material_versions", "materials"
+  add_foreign_key "material_versions", "materials", column: "parent_id"
+  add_foreign_key "material_versions", "tags"
+  add_foreign_key "material_versions", "users", column: "created_by_user_id"
+  add_foreign_key "material_versions", "users", column: "updated_by_user_id"
+  add_foreign_key "materials", "materials", column: "parent_id"
+  add_foreign_key "materials", "tags"
+  add_foreign_key "materials", "users", column: "created_by_user_id"
+  add_foreign_key "materials", "users", column: "updated_by_user_id"
   add_foreign_key "nico_tag_relations", "tags"
   add_foreign_key "nico_tag_relations", "tags", column: "nico_tag_id"
   add_foreign_key "post_similarities", "posts"
@@ -320,6 +382,8 @@ ActiveRecord::Schema[8.0].define(version: 2026_03_17_015000) do
   add_foreign_key "user_ips", "users"
   add_foreign_key "user_post_views", "posts"
   add_foreign_key "user_post_views", "users"
+  add_foreign_key "wiki_assets", "users", column: "created_by_user_id"
+  add_foreign_key "wiki_assets", "wiki_pages"
   add_foreign_key "wiki_pages", "tag_names"
   add_foreign_key "wiki_pages", "users", column: "created_user_id"
   add_foreign_key "wiki_pages", "users", column: "updated_user_id"