diff --git a/packages/backend/src/models/entities/Flash.ts b/packages/backend/src/models/entities/Flash.ts
index 775577f819..38e023332e 100644
--- a/packages/backend/src/models/entities/Flash.ts
+++ b/packages/backend/src/models/entities/Flash.ts
@@ -67,7 +67,7 @@ export class MiFlash {
 	 * private ... プロフィールには表示しない
 	 */
 	@Column('varchar', {
-		default: 'public',
+		length: 512, default: 'public',
 	})
 	public visibility: 'public' | 'private';
 }