diff --git a/packages/backend/src/server/api/endpoints/bubble-game/register.ts b/packages/backend/src/server/api/endpoints/bubble-game/register.ts
index f092d16a70..db462397ee 100644
--- a/packages/backend/src/server/api/endpoints/bubble-game/register.ts
+++ b/packages/backend/src/server/api/endpoints/bubble-game/register.ts
@@ -63,8 +63,8 @@ export default class extends Endpoint<typeof meta, typeof paramDef> { // eslint-
 				throw new ApiError(meta.errors.invalidSeed);
 			}
 
-			// シードが古すぎる(1時間以上前)のも弾く
-			if (seedDate.getTime() < now.getTime() - 1000 * 60 * 60) {
+			// シードが古すぎる(6時間以上前)のも弾く
+			if (seedDate.getTime() < now.getTime() - 1000 * 60 * 60 * 6) {
 				throw new ApiError(meta.errors.invalidSeed);
 			}