diff --git a/config/i18n-tasks.yml b/config/i18n-tasks.yml
index 853d148b289ad33cb551119d03348d90bb512ba8..20c13424967dd1233a48e66c63fa9180e1d45c73 100644
--- a/config/i18n-tasks.yml
+++ b/config/i18n-tasks.yml
@@ -54,3 +54,4 @@ ignore_unused:
   - 'simple_form.{error_notification,required}.:'
   - 'errors.messages.*'
   - 'activerecord.errors.models.doorkeeper/*'
+  - 'errors.429'
diff --git a/config/initializers/rack_attack.rb b/config/initializers/rack_attack.rb
index 3ebe3946207b9a91052e4d9757cb015b9e5d9d2a..d5cd77b3461dad7e4455ef77b38bda5a327f3d61 100644
--- a/config/initializers/rack_attack.rb
+++ b/config/initializers/rack_attack.rb
@@ -38,6 +38,6 @@ class Rack::Attack
       'X-RateLimit-Reset'     => (now + (match_data[:period] - now.to_i % match_data[:period])).iso8601(6),
     }
 
-    [429, headers, [{ error: 'Throttled' }.to_json]]
+    [429, headers, [{ error: I18n.t('errors.429') }.to_json]]
   end
 end
diff --git a/config/locales/en.yml b/config/locales/en.yml
index 26ecac7bcde2d9b994d606e180166688f3ec4b3a..936aa38d936a498b7c17242de4777f359c35f9c5 100644
--- a/config/locales/en.yml
+++ b/config/locales/en.yml
@@ -223,6 +223,7 @@ en:
     '422':
       content: Security verification failed. Are you blocking cookies?
       title: Security verification failed
+    '429': Throttled
   exports:
     blocks: You block
     csv: CSV
diff --git a/config/locales/ja.yml b/config/locales/ja.yml
index cc79ca5a8fe7d640b3458ba30b68157540b231c8..af5e77d1428c9916b64d071748f45772c2be92f1 100644
--- a/config/locales/ja.yml
+++ b/config/locales/ja.yml
@@ -222,6 +222,7 @@ ja:
     '422':
       content: セキュリティ認証に失敗しました。Cookieをブロックしていませんか？
       title: セキュリティ認証に失敗
+    '429': リクエストの制限に達しました。
   exports:
     blocks: ブロック
     csv: CSV