diff --git a/backend/config/environments/production.rb b/backend/config/environments/production.rb
index d1ad8cc..3038b02 100644
--- a/backend/config/environments/production.rb
+++ b/backend/config/environments/production.rb
@@ -18,8 +18,7 @@ Rails.application.configure do
   # Enable serving of images, stylesheets, and JavaScripts from an asset server.
   # config.asset_host = "http://assets.example.com"
 
-  # TODO: オブスト契約したら :r2 に変更する．
-  config.active_storage.service = :local
+  config.active_storage.service = :r2
 
   # Assume all access to the app is happening through a SSL-terminating reverse proxy.
   config.assume_ssl = true