diff --git a/backend/spec/factories/ip_addresses.rb b/backend/spec/factories/ip_addresses.rb
new file mode 100644
index 0000000..6ffc363
--- /dev/null
+++ b/backend/spec/factories/ip_addresses.rb
@@ -0,0 +1,10 @@
+FactoryBot.define do
+  factory :ip_address do
+    ip_address { IPAddr.new('203.0.113.10').hton }
+    banned_at { nil }
+
+    trait :banned do
+      banned_at { Time.current }
+    end
+  end
+end
diff --git a/backend/spec/factories/users.rb b/backend/spec/factories/users.rb
index f7db70a..9225a23 100644
--- a/backend/spec/factories/users.rb
+++ b/backend/spec/factories/users.rb
@@ -1,15 +1,24 @@
 FactoryBot.define do
   factory :user do
-    name { "test-user" }
+    name { nil }
     inheritance_code { SecureRandom.uuid }
-    role { "guest" }
+    role { 'guest' }
+    banned_at { nil }
+
+    trait :guest do
+      role { 'guest' }
+    end
 
     trait :member do
-      role { "member" }
+      role { 'member' }
     end
 
     trait :admin do
       role { 'admin' }
     end
+
+    trait :banned do
+      banned_at { Time.current }
+    end
   end
 end
diff --git a/backend/spec/requests/users_spec.rb b/backend/spec/requests/users_spec.rb
index 1f28e95..67c556f 100644
--- a/backend/spec/requests/users_spec.rb
+++ b/backend/spec/requests/users_spec.rb
@@ -1,109 +1,266 @@
-require "rails_helper"
+require 'rails_helper'
+
+RSpec.describe 'Users', type: :request do
+  let(:remote_ip) { '203.0.113.10' }
+
+  before do
+    allow_any_instance_of(ActionDispatch::Request)
+      .to receive(:remote_ip)
+      .and_return(remote_ip)
+  end
+
+  def auth_headers(user)
+    { 'X-Transfer-Code' => user.inheritance_code }
+  end
+
+  describe 'POST /users' do
+    it 'creates guest user, IpAddress and UserIp, and returns code' do
+      expect {
+        post '/users'
+      }.to change(User, :count).by(1)
+        .and change(IpAddress, :count).by(1)
+        .and change(UserIp, :count).by(1)
 
-RSpec.describe "Users", type: :request do
-  describe "POST /users" do
-    it "creates guest user and returns code" do
-      post "/users"
       expect(response).to have_http_status(:created)
-      expect(json["code"]).to be_present
-      expect(json["user"]["role"]).to eq("guest")
+      expect(json['code']).to be_present
+      expect(json['user']['role']).to eq('guest')
+
+      user = User.last
+      ip_address = IpAddress.find_by(ip_address: IPAddr.new(remote_ip).hton)
+
+      expect(user.role).to eq('guest')
+      expect(ip_address).to be_present
+      expect(UserIp.exists?(user:, ip_address:)).to eq(true)
+    end
+
+    it 'returns 403 and does not create user when current IP address is banned' do
+      IpAddress.create!(
+        ip_address: IPAddr.new(remote_ip).hton,
+        banned_at: Time.current
+      )
+
+      expect {
+        post '/users'
+      }.not_to change(User, :count)
+
+      expect(response).to have_http_status(:forbidden)
+      expect(UserIp.count).to eq(0)
     end
   end
 
-  describe "POST /users/code/renew" do
-    it "returns 401 when not logged in" do
-      sign_out
-      post "/users/code/renew"
+  describe 'POST /users/code/renew' do
+    it 'returns 401 when not logged in' do
+      post '/users/code/renew'
+
       expect(response).to have_http_status(:unauthorized)
     end
+
+    it 'returns 403 when current user is banned' do
+      user = create(:user, :banned)
+
+      post '/users/code/renew', headers: auth_headers(user)
+
+      expect(response).to have_http_status(:forbidden)
+    end
+
+    it 'returns 403 when current IP address is banned' do
+      user = create(:user)
+
+      IpAddress.create!(
+        ip_address: IPAddr.new(remote_ip).hton,
+        banned_at: Time.current
+      )
+
+      post '/users/code/renew', headers: auth_headers(user)
+
+      expect(response).to have_http_status(:forbidden)
+    end
   end
 
-  describe "PUT /users/:id" do
-    let(:user) { create(:user, name: "old-name", role: "guest") }
+  describe 'PUT /users/:id' do
+    let(:user) { create(:user, name: 'old-name', role: 'guest') }
+
+    it 'returns 401 when current_user id mismatch' do
+      other_user = create(:user)
+
+      put "/users/#{user.id}",
+          params: { name: 'new-name' },
+          headers: auth_headers(other_user)
 
-    it "returns 401 when current_user id mismatch" do
-      sign_in_as(create(:user))
-      put "/users/#{user.id}", params: { name: "new-name" }
       expect(response).to have_http_status(:unauthorized)
     end
 
-    it "returns 400 when name is blank" do
-      sign_in_as(user)
-      put "/users/#{user.id}", params: { name: "   " }
+    it 'returns 400 when name is blank' do
+      put "/users/#{user.id}",
+          params: { name: '   ' },
+          headers: auth_headers(user)
+
       expect(response).to have_http_status(:bad_request)
     end
 
-    it "updates name and returns 201 with user slice" do
-      sign_in_as(user)
-      put "/users/#{user.id}", params: { name: "new-name" }
+    it 'updates name and returns user slice' do
+      put "/users/#{user.id}",
+          params: { name: 'new-name' },
+          headers: auth_headers(user)
 
       expect(response).to have_http_status(:ok)
-      expect(json["id"]).to eq(user.id)
-      expect(json["name"]).to eq("new-name")
+      expect(json['id']).to eq(user.id)
+      expect(json['name']).to eq('new-name')
 
       user.reload
-      expect(user.name).to eq("new-name")
+      expect(user.name).to eq('new-name')
+    end
+
+    it 'returns 403 when current user is banned' do
+      user.update!(banned_at: Time.current)
+
+      put "/users/#{user.id}",
+          params: { name: 'new-name' },
+          headers: auth_headers(user)
+
+      expect(response).to have_http_status(:forbidden)
+
+      user.reload
+      expect(user.name).to eq('old-name')
+    end
+
+    it 'returns 403 when current IP address is banned' do
+      IpAddress.create!(
+        ip_address: IPAddr.new(remote_ip).hton,
+        banned_at: Time.current
+      )
+
+      put "/users/#{user.id}",
+          params: { name: 'new-name' },
+          headers: auth_headers(user)
+
+      expect(response).to have_http_status(:forbidden)
+
+      user.reload
+      expect(user.name).to eq('old-name')
     end
   end
 
-  describe "POST /users/verify" do
-    it "returns valid:false when code not found" do
-      post "/users/verify", params: { code: "nope" }
+  describe 'POST /users/verify' do
+    it 'returns valid:false when code not found' do
+      post '/users/verify', params: { code: 'nope' }
+
       expect(response).to have_http_status(:ok)
-      expect(json["valid"]).to eq(false)
+      expect(json['valid']).to eq(false)
     end
 
-    it "creates IpAddress and UserIp, and returns valid:true with user slice" do
-      user = create(:user, inheritance_code: SecureRandom.uuid, role: "guest")
+    it 'returns 403 when current IP address is banned' do
+      user = create(:user, inheritance_code: SecureRandom.uuid, role: 'guest')
+
+      IpAddress.create!(
+        ip_address: IPAddr.new(remote_ip).hton,
+        banned_at: Time.current
+      )
+
+      expect {
+        post '/users/verify', params: { code: user.inheritance_code }
+      }.not_to change(UserIp, :count)
+
+      expect(response).to have_http_status(:forbidden)
+    end
+
+    it 'returns 403 when verified user is banned' do
+      user = create(
+        :user,
+        :banned,
+        inheritance_code: SecureRandom.uuid,
+        role: 'guest'
+      )
+
+      expect {
+        post '/users/verify', params: { code: user.inheritance_code }
+      }.not_to change(UserIp, :count)
+
+      expect(response).to have_http_status(:forbidden)
+    end
 
-      # request.remote_ip を固定
-      allow_any_instance_of(ActionDispatch::Request).to receive(:remote_ip).and_return("203.0.113.10")
+    it 'creates IpAddress and UserIp, and returns valid:true with user slice' do
+      user = create(:user, inheritance_code: SecureRandom.uuid, role: 'guest')
 
       expect {
-        post "/users/verify", params: { code: user.inheritance_code }
+        post '/users/verify', params: { code: user.inheritance_code }
       }.to change(UserIp, :count).by(1)
+        .and change(IpAddress, :count).by(1)
 
       expect(response).to have_http_status(:ok)
-      expect(json["valid"]).to eq(true)
-      expect(json["user"]["id"]).to eq(user.id)
-      expect(json["user"]["inheritance_code"]).to eq(user.inheritance_code)
-      expect(json["user"]["role"]).to eq("guest")
+      expect(json['valid']).to eq(true)
+      expect(json['user']['id']).to eq(user.id)
+      expect(json['user']['inheritance_code']).to eq(user.inheritance_code)
+      expect(json['user']['role']).to eq('guest')
 
-      # ついでに IpAddress もできてることを確認（ipの保存形式がバイナリでも count で見れる）
-      expect(IpAddress.count).to be >= 1
+      ip_address = IpAddress.find_by(ip_address: IPAddr.new(remote_ip).hton)
+      expect(ip_address).to be_present
+      expect(UserIp.exists?(user:, ip_address:)).to eq(true)
     end
 
-    it "is idempotent for same user+ip (does not create duplicate UserIp)" do
-      user = create(:user, inheritance_code: SecureRandom.uuid, role: "guest")
-      allow_any_instance_of(ActionDispatch::Request).to receive(:remote_ip).and_return("203.0.113.10")
+    it 'is idempotent for same user and same IP address' do
+      user = create(:user, inheritance_code: SecureRandom.uuid, role: 'guest')
 
-      post "/users/verify", params: { code: user.inheritance_code }
+      post '/users/verify', params: { code: user.inheritance_code }
       expect(response).to have_http_status(:ok)
 
       expect {
-        post "/users/verify", params: { code: user.inheritance_code }
+        post '/users/verify', params: { code: user.inheritance_code }
       }.not_to change(UserIp, :count)
 
       expect(response).to have_http_status(:ok)
-      expect(json["valid"]).to eq(true)
+      expect(json['valid']).to eq(true)
+    end
+
+    it 'creates another UserIp for same user and different IP address' do
+      user = create(:user, inheritance_code: SecureRandom.uuid, role: 'guest')
+
+      post '/users/verify', params: { code: user.inheritance_code }
+      expect(response).to have_http_status(:ok)
+
+      allow_any_instance_of(ActionDispatch::Request)
+        .to receive(:remote_ip)
+        .and_return('203.0.113.11')
+
+      expect {
+        post '/users/verify', params: { code: user.inheritance_code }
+      }.to change(UserIp, :count).by(1)
+
+      expect(response).to have_http_status(:ok)
+      expect(json['valid']).to eq(true)
     end
   end
 
-  describe "GET /users/me" do
-    it "returns 404 when code not found" do
-      get "/users/me", params: { code: "nope" }
+  describe 'GET /users/me' do
+    it 'returns 404 when code not found' do
+      get '/users/me', params: { code: 'nope' }
+
       expect(response).to have_http_status(:not_found)
     end
 
-    it "returns user slice when found" do
-      user = create(:user, inheritance_code: SecureRandom.uuid, name: "me", role: "guest")
-      get "/users/me", params: { code: user.inheritance_code }
+    it 'returns user slice when found' do
+      user = create(:user, inheritance_code: SecureRandom.uuid, name: 'me', role: 'guest')
+
+      get '/users/me', params: { code: user.inheritance_code }
 
       expect(response).to have_http_status(:ok)
-      expect(json["id"]).to eq(user.id)
-      expect(json["name"]).to eq("me")
-      expect(json["inheritance_code"]).to eq(user.inheritance_code)
-      expect(json["role"]).to eq("guest")
+      expect(json['id']).to eq(user.id)
+      expect(json['name']).to eq('me')
+      expect(json['inheritance_code']).to eq(user.inheritance_code)
+      expect(json['role']).to eq('guest')
+    end
+
+    it 'returns 403 when current IP address is banned' do
+      user = create(:user, inheritance_code: SecureRandom.uuid)
+
+      IpAddress.create!(
+        ip_address: IPAddr.new(remote_ip).hton,
+        banned_at: Time.current
+      )
+
+      get '/users/me', params: { code: user.inheritance_code }
+
+      expect(response).to have_http_status(:forbidden)
     end
   end
 end
diff --git a/backend/spec/support/test_records.rb b/backend/spec/support/test_records.rb
index 350b8da..b6a7cd5 100644
--- a/backend/spec/support/test_records.rb
+++ b/backend/spec/support/test_records.rb
@@ -2,14 +2,12 @@ module TestRecords
   def create_member_user!
     User.create!(name: 'spec user',
                  inheritance_code: SecureRandom.hex(16),
-                 role: 'member',
-                 banned: false)
+                 role: 'member')
   end
 
   def create_admin_user!
     User.create!(name: 'spec admin',
                  inheritance_code: SecureRandom.hex(16),
-                 role: 'admin',
-                 banned: false)
+                 role: 'admin')
   end
 end