diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 19f96af..079b7de 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -15,7 +15,7 @@ jobs:
       - name: Setup Ruby and install gems
         uses: ruby/setup-ruby@v1
         with:
-          ruby-version: 2.7
+          ruby-version: 3.4.4
           bundler-cache: true
 
       - name: Run linters
@@ -26,7 +26,7 @@ jobs:
     runs-on: ubuntu-latest
     strategy:
       matrix:
-        ruby-version: [2.6, 2.7, 3.0]
+        ruby-version: [2.6, 2.7, 3.0, 3.4.4]
     steps:
     - name: Checkout code
       uses: actions/checkout@v2
diff --git a/.rubocop.yml b/.rubocop.yml
index 2fbb3c9..84aecf4 100644
--- a/.rubocop.yml
+++ b/.rubocop.yml
@@ -1,5 +1,5 @@
 AllCops:
-  TargetRubyVersion: 2.6
+  TargetRubyVersion: 3.0
   NewCops: enable
 
 Metrics/BlockLength:
diff --git a/.ruby-version b/.ruby-version
index 37c2961..f989260 100644
--- a/.ruby-version
+++ b/.ruby-version
@@ -1 +1 @@
-2.7.2
+3.4.4
diff --git a/microcms.gemspec b/microcms.gemspec
index 9fc6652..cf5b3a0 100644
--- a/microcms.gemspec
+++ b/microcms.gemspec
@@ -10,7 +10,7 @@ Gem::Specification.new do |spec|
   spec.summary       = 'microCMS Ruby SDK'
   spec.description   = 'microCMS Ruby SDK'
   spec.homepage      = 'https://github.com/microcmsio/microcms-ruby-sdk'
-  spec.required_ruby_version = Gem::Requirement.new('>= 2.6.0')
+  spec.required_ruby_version = Gem::Requirement.new('>= 3.0.0')
 
   spec.metadata['homepage_uri']    = spec.homepage
   spec.metadata['source_code_uri'] = spec.homepage