diff --git a/.github/workflows/pull_request.yml b/.github/workflows/pull_request.yml
index 501caed3..9711ed72 100644
--- a/.github/workflows/pull_request.yml
+++ b/.github/workflows/pull_request.yml
@@ -15,7 +15,6 @@ jobs:
       matrix:
         # https://www.ruby-lang.org/en/downloads/branches/
         ruby:
-          - '3.2'
           - '3.3'
           - '3.4'
           - '4.0'
diff --git a/README.md b/README.md
index 7ea1f405..a915bb1f 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@ Also, generated documentation by YARD is available.
 - https://line.github.io/line-bot-sdk-ruby/_index.html
 
 ## Requirements
-This library requires Ruby 3.2 or later.
+This library requires Ruby 3.3 or later.
 
 ## Installation
 
diff --git a/line-bot-api.gemspec b/line-bot-api.gemspec
index a3bed0ae..4ca8ac11 100644
--- a/line-bot-api.gemspec
+++ b/line-bot-api.gemspec
@@ -22,7 +22,7 @@ Gem::Specification.new do |spec|
     "source_code_uri" => spec.homepage,
   }
 
-  spec.required_ruby_version = '>= 3.2.0'
+  spec.required_ruby_version = '>= 3.3.0'
 
   spec.add_runtime_dependency "multipart-post", "~> 2.4"