diff --git a/README.md b/README.md
index 5abafff..cf5a2db 100644
--- a/README.md
+++ b/README.md
@@ -2,4 +2,5 @@
 
 [![Build Status](https://travis-ci.org/ryoichi-obara/study-marking-201709.svg?branch=master)](https://travis-ci.org/ryoichi-obara/study-marking-201709)
 [![Coverage Status](https://coveralls.io/repos/github/ryoichi-obara/study-marking-201709/badge.svg?branch=master)](https://coveralls.io/github/ryoichi-obara/study-marking-201709?branch=master)
+[![Maintainability](https://api.codeclimate.com/v1/badges/f1dc6d92757dad4d48e6/maintainability)](https://codeclimate.com/github/ryoichi-obara/study-marking-201709/maintainability)
 [![MIT License](http://img.shields.io/badge/license-MIT-blue.svg?style=flat)](LICENSE)