diff --git a/main.rb b/main.rb
index 7530c0a..dffec51 100644
--- a/main.rb
+++ b/main.rb
@@ -11,7 +11,7 @@
 http.use_ssl = true
 
 body = "body=#{params[:message]}"
-headers = { "X-ChatWorkToken" => "#{params[:token]}" }
+headers = { 'X-ChatWorkToken' => "#{params[:token]}" }
 
 response = http.post(uri.path, body, headers)