diff --git a/backend/app/controllers/posts_controller.rb b/backend/app/controllers/posts_controller.rb
index 79002f8..fb0d8b5 100644
--- a/backend/app/controllers/posts_controller.rb
+++ b/backend/app/controllers/posts_controller.rb
@@ -80,7 +80,7 @@ class PostsController < ApplicationController
     # TODO: URL が正規のものがチェック，不正ならエラー
     # TODO: URL は必須にする（タイトルは省略可）．
     # TODO: サイトに応じて thumbnail_base 設定
-    title = params[:title]
+    title = params[:title].presence
     url = params[:url]
     thumbnail = params[:thumbnail]
     tag_names = params[:tags].to_s.split(' ')
@@ -121,7 +121,7 @@ class PostsController < ApplicationController
     return head :unauthorized unless current_user
     return head :forbidden unless current_user.member?
 
-    title = params[:title]
+    title = params[:title].presence
     tag_names = params[:tags].to_s.split(' ')
     original_created_from = params[:original_created_from]
     original_created_before = params[:original_created_before]
diff --git a/backend/db/migrate/20260107034300_make_title_nullable_in_posts.rb b/backend/db/migrate/20260107034300_make_title_nullable_in_posts.rb
new file mode 100644
index 0000000..80e6858
--- /dev/null
+++ b/backend/db/migrate/20260107034300_make_title_nullable_in_posts.rb
@@ -0,0 +1,28 @@
+class MakeTitleNullableInPosts < ActiveRecord::Migration[7.0]
+  def up
+    change_column_null :posts, :title, true
+
+    execute <<~SQL
+      UPDATE
+        posts
+      SET
+        title = NULL
+      WHERE
+        title = ''
+    SQL
+  end
+
+  def down
+    execute <<~SQL
+      UPDATE
+        posts
+      SET
+        title = ''
+      WHERE
+        title IS NULL
+    SQL
+
+    change_column_null :posts, :title, false
+  end
+end
+