diff --git a/Gemfile b/Gemfile
index 5a4c145..ccabfdc 100644
--- a/Gemfile
+++ b/Gemfile
@@ -4,6 +4,6 @@ gemspec
 
 gem "bundler", "~> 2.4"
 gem "rake", "~> 13.2.1"
+gem "rubocop-fluentd", "~> 0.2.0"
 gem "test-unit", "~> 3.0"
 gem "test-unit-rr", "~> 1.0.5"
-gem "rubocop-fluentd", "~> 0.2.0"
diff --git a/lib/fluent/plugin/in_fluent_package_update_notifier.rb b/lib/fluent/plugin/in_fluent_package_update_notifier.rb
index 458d7fd..074890c 100644
--- a/lib/fluent/plugin/in_fluent_package_update_notifier.rb
+++ b/lib/fluent/plugin/in_fluent_package_update_notifier.rb
@@ -72,7 +72,7 @@ def check_fluent_pacakge_update_information
           checker = Fluent::Plugin::FluentPackage::UpdateChecker.new(options)
           checker.run
         rescue => e
-          log.error "Failed to check updates: #{e.message}"
+          log.error { "Failed to check updates: #{e.message}" }
         end
       end
     end