diff --git a/db/migrate/20230814055132_change_memos_content_size.rb b/db/migrate/20230814055132_change_memos_content_size.rb
index e74ec590..2fc923ef 100644
--- a/db/migrate/20230814055132_change_memos_content_size.rb
+++ b/db/migrate/20230814055132_change_memos_content_size.rb
@@ -1,5 +1,5 @@
 class ChangeMemosContentSize < ActiveRecord::Migration[5.2]
   def change
-    change_column :memos, :content, :longtext
+    execute("ALTER TABLE `memos` MODIFY `content` longtext CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;")
   end
 end