diff --git a/.circleci/config.yml b/.circleci/config.yml
index 9dd6de46..c76072a8 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -1,7 +1,7 @@
 jobs:
   build:
     docker:
-      - image: cimg/ruby:3.1.2
+      - image: cimg/ruby:3.3.5
     environment:
       RAILS_ENV: test
     steps:
diff --git a/README.markdown b/README.markdown
index e9263837..a768ef10 100644
--- a/README.markdown
+++ b/README.markdown
@@ -1,6 +1,6 @@
 # CodeRay
 
-[![CircleCI](https://dl.circleci.com/status-badge/img/gh/rubychan/coderay/tree/master.svg?style=svg&circle-token=cdc86dfde1b86067977f0fc1d3cbdd7e3171c873)](https://dl.circleci.com/status-badge/redirect/gh/rubychan/coderay/tree/master) [![Gem Version](https://badge.fury.io/rb/coderay.svg)](https://badge.fury.io/rb/coderay) [![Maintainability](https://api.codeclimate.com/v1/badges/e015bbd5eab45d948b6b/maintainability)](https://codeclimate.com/github/rubychan/coderay/maintainability)
+[![CircleCI](https://dl.circleci.com/status-badge/img/gh/rubychan/coderay/tree/master.svg?style=svg&circle-token=CCIPRJ_BbFff6nMhNtPdrCBNMDxNq_be00bbb00849a29d8d8d2e28e7b84cbf76a9ee5c)](https://dl.circleci.com/status-badge/redirect/gh/rubychan/coderay/tree/master) [![Gem Version](https://badge.fury.io/rb/coderay.svg)](https://badge.fury.io/rb/coderay) [![Maintainability](https://api.codeclimate.com/v1/badges/e015bbd5eab45d948b6b/maintainability)](https://codeclimate.com/github/rubychan/coderay/maintainability)
 
 ## About