diff --git a/Gemfile b/Gemfile
index 20ae645f3..1704bcd26 100644
--- a/Gemfile
+++ b/Gemfile
@@ -13,6 +13,6 @@ gem 'zeus', require: false
 
 # YARD
 gem 'fssm'
-gem 'pygments.rb'
+gem 'rouge'
 gem 'redcarpet'
 gem 'yard'
diff --git a/Gemfile.lock b/Gemfile.lock
index f4b0e879a..629a48822 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -11,7 +11,6 @@ GEM
     diff-lcs (1.3)
     fssm (0.2.10)
     method_source (1.0.0)
-    multi_json (1.14.1)
     parallel (1.19.2)
     parser (2.7.1.4)
       ast (~> 2.4.1)
@@ -21,14 +20,13 @@ GEM
     pry-byebug (3.9.0)
       byebug (~> 11.0)
       pry (~> 0.13.0)
-    pygments.rb (1.2.1)
-      multi_json (>= 1.0.0)
     rack (2.2.2)
     rainbow (3.0.0)
     rake (13.0.1)
     redcarpet (3.5.0)
     regexp_parser (1.7.1)
     rexml (3.2.4)
+    rouge (3.22.0)
     rspec (3.9.0)
       rspec-core (~> 3.9.0)
       rspec-expectations (~> 3.9.0)
@@ -73,9 +71,9 @@ DEPENDENCIES
   fssm
   pry
   pry-byebug
-  pygments.rb
   rake (= 13.0.1)
   redcarpet
+  rouge
   rspec (~> 3.9)
   rubocop
   rubocop-rails
diff --git a/doc_config/yard/setup.rb b/doc_config/yard/setup.rb
index eb654f5b6..6483b4c22 100644
--- a/doc_config/yard/setup.rb
+++ b/doc_config/yard/setup.rb
@@ -1,20 +1,20 @@
 YARD::Templates::Engine.register_template_path(File.dirname(__FILE__) + '/templates')
 
-require 'pygments.rb'
+require 'rouge'
 
 module YARD
   module Templates
     module Helpers
       module HtmlSyntaxHighlightHelper
         def html_syntax_highlight_ruby(source)
-          highlight_with_pygments(:ruby, source)
+          highlight(:ruby, source)
         end
 
         private
 
-        def highlight_with_pygments(language, source)
-          html = Pygments.highlight(source, lexer: language.to_s)
-          html.sub(%r{\A<div class="highlight">\s*<pre>}, '').sub(%r{</pre>\s*</div>\Z}, '')
+        def highlight(language, source)
+          lexer = Rouge::Lexers.const_get(language.capitalize)
+          Rouge::Formatters::HTML.new.format(lexer.new.lex(source))
         end
       end
     end
diff --git a/gemfiles/rails_4_2.gemfile b/gemfiles/rails_4_2.gemfile
index b90bb032c..b58c8b2fe 100644
--- a/gemfiles/rails_4_2.gemfile
+++ b/gemfiles/rails_4_2.gemfile
@@ -13,7 +13,7 @@ gem "rubocop-rails", require: false
 gem "warnings_logger"
 gem "zeus", require: false
 gem "fssm"
-gem "pygments.rb"
+gem "rouge"
 gem "redcarpet"
 gem "yard"
 gem "spring"
diff --git a/gemfiles/rails_4_2.gemfile.lock b/gemfiles/rails_4_2.gemfile.lock
index 7d9bc6912..cbbc45ff8 100644
--- a/gemfiles/rails_4_2.gemfile.lock
+++ b/gemfiles/rails_4_2.gemfile.lock
@@ -83,7 +83,6 @@ GEM
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.13.0)
-    multi_json (1.14.1)
     nokogiri (1.10.7)
       mini_portile2 (~> 2.4.0)
     parallel (1.19.2)
@@ -98,8 +97,6 @@ GEM
     pry-byebug (3.9.0)
       byebug (~> 11.0)
       pry (~> 0.13.0)
-    pygments.rb (1.2.1)
-      multi_json (>= 1.0.0)
     rack (1.6.13)
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -138,6 +135,7 @@ GEM
     redcarpet (3.5.0)
     regexp_parser (1.7.1)
     rexml (3.2.4)
+    rouge (3.22.0)
     rspec (3.9.0)
       rspec-core (~> 3.9.0)
       rspec-expectations (~> 3.9.0)
@@ -233,10 +231,10 @@ DEPENDENCIES
   protected_attributes (~> 1.0.6)
   pry
   pry-byebug
-  pygments.rb
   rails (= 4.2.11.1)
   rake (= 13.0.1)
   redcarpet
+  rouge
   rspec (~> 3.9)
   rspec-rails (~> 3.9)
   rubocop
diff --git a/gemfiles/rails_5_0.gemfile b/gemfiles/rails_5_0.gemfile
index 8295baca9..0bb6362fe 100644
--- a/gemfiles/rails_5_0.gemfile
+++ b/gemfiles/rails_5_0.gemfile
@@ -13,7 +13,7 @@ gem "rubocop-rails", require: false
 gem "warnings_logger"
 gem "zeus", require: false
 gem "fssm"
-gem "pygments.rb"
+gem "rouge"
 gem "redcarpet"
 gem "yard"
 gem "spring"
diff --git a/gemfiles/rails_5_0.gemfile.lock b/gemfiles/rails_5_0.gemfile.lock
index e5e4304c2..ecb83c944 100644
--- a/gemfiles/rails_5_0.gemfile.lock
+++ b/gemfiles/rails_5_0.gemfile.lock
@@ -76,7 +76,6 @@ GEM
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.13.0)
-    multi_json (1.14.1)
     nio4r (2.5.2)
     nokogiri (1.10.7)
       mini_portile2 (~> 2.4.0)
@@ -91,8 +90,6 @@ GEM
       byebug (~> 11.0)
       pry (~> 0.13.0)
     puma (3.12.2)
-    pygments.rb (1.2.1)
-      multi_json (>= 1.0.0)
     rack (2.2.2)
     rack-test (0.6.3)
       rack (>= 1.0)
@@ -131,6 +128,7 @@ GEM
     redcarpet (3.5.0)
     regexp_parser (1.7.1)
     rexml (3.2.4)
+    rouge (3.22.0)
     rspec (3.9.0)
       rspec-core (~> 3.9.0)
       rspec-expectations (~> 3.9.0)
@@ -225,11 +223,11 @@ DEPENDENCIES
   pry
   pry-byebug
   puma (~> 3.0)
-  pygments.rb
   rails (= 5.0.7.2)
   rails-controller-testing (>= 1.0.1)
   rake (= 13.0.1)
   redcarpet
+  rouge
   rspec (~> 3.9)
   rspec-rails (~> 3.9)
   rubocop
diff --git a/gemfiles/rails_5_1.gemfile b/gemfiles/rails_5_1.gemfile
index ebe601837..ac7a944d6 100644
--- a/gemfiles/rails_5_1.gemfile
+++ b/gemfiles/rails_5_1.gemfile
@@ -13,7 +13,7 @@ gem "rubocop-rails", require: false
 gem "warnings_logger"
 gem "zeus", require: false
 gem "fssm"
-gem "pygments.rb"
+gem "rouge"
 gem "redcarpet"
 gem "yard"
 gem "spring"
diff --git a/gemfiles/rails_5_1.gemfile.lock b/gemfiles/rails_5_1.gemfile.lock
index 58e4412c7..3c60b9d00 100644
--- a/gemfiles/rails_5_1.gemfile.lock
+++ b/gemfiles/rails_5_1.gemfile.lock
@@ -83,7 +83,6 @@ GEM
     mini_mime (1.0.2)
     mini_portile2 (2.4.0)
     minitest (5.13.0)
-    multi_json (1.14.1)
     nio4r (2.5.2)
     nokogiri (1.10.7)
       mini_portile2 (~> 2.4.0)
@@ -99,8 +98,6 @@ GEM
       pry (~> 0.13.0)
     public_suffix (4.0.1)
     puma (3.12.2)
-    pygments.rb (1.2.1)
-      multi_json (>= 1.0.0)
     rack (2.2.2)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -139,6 +136,7 @@ GEM
     redcarpet (3.5.0)
     regexp_parser (1.7.1)
     rexml (3.2.4)
+    rouge (3.22.0)
     rspec (3.9.0)
       rspec-core (~> 3.9.0)
       rspec-expectations (~> 3.9.0)
@@ -240,11 +238,11 @@ DEPENDENCIES
   pry
   pry-byebug
   puma (~> 3.7)
-  pygments.rb
   rails (= 5.1.7)
   rails-controller-testing (>= 1.0.1)
   rake (= 13.0.1)
   redcarpet
+  rouge
   rspec (~> 3.9)
   rspec-rails (~> 3.9)
   rubocop
diff --git a/gemfiles/rails_5_2.gemfile b/gemfiles/rails_5_2.gemfile
index c53dac15c..7a253fe31 100644
--- a/gemfiles/rails_5_2.gemfile
+++ b/gemfiles/rails_5_2.gemfile
@@ -13,7 +13,7 @@ gem "rubocop-rails", require: false
 gem "warnings_logger"
 gem "zeus", require: false
 gem "fssm"
-gem "pygments.rb"
+gem "rouge"
 gem "redcarpet"
 gem "yard"
 gem "spring"
diff --git a/gemfiles/rails_5_2.gemfile.lock b/gemfiles/rails_5_2.gemfile.lock
index 079a57541..52124b0d4 100644
--- a/gemfiles/rails_5_2.gemfile.lock
+++ b/gemfiles/rails_5_2.gemfile.lock
@@ -99,7 +99,6 @@ GEM
     mini_portile2 (2.4.0)
     minitest (5.13.0)
     msgpack (1.3.1)
-    multi_json (1.14.1)
     nio4r (2.5.2)
     nokogiri (1.10.7)
       mini_portile2 (~> 2.4.0)
@@ -115,8 +114,6 @@ GEM
       pry (~> 0.13.0)
     public_suffix (4.0.1)
     puma (3.12.2)
-    pygments.rb (1.2.1)
-      multi_json (>= 1.0.0)
     rack (2.2.2)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -156,6 +153,7 @@ GEM
     redcarpet (3.5.0)
     regexp_parser (1.7.1)
     rexml (3.2.4)
+    rouge (3.22.0)
     rspec (3.9.0)
       rspec-core (~> 3.9.0)
       rspec-expectations (~> 3.9.0)
@@ -259,11 +257,11 @@ DEPENDENCIES
   pry
   pry-byebug
   puma (~> 3.11)
-  pygments.rb
   rails (= 5.2.4.1)
   rails-controller-testing (>= 1.0.1)
   rake (= 13.0.1)
   redcarpet
+  rouge
   rspec (~> 3.9)
   rspec-rails (~> 3.9)
   rubocop
diff --git a/gemfiles/rails_6_0.gemfile b/gemfiles/rails_6_0.gemfile
index f7d5c94d5..c702b8203 100644
--- a/gemfiles/rails_6_0.gemfile
+++ b/gemfiles/rails_6_0.gemfile
@@ -13,7 +13,7 @@ gem "rubocop-rails", require: false
 gem "warnings_logger"
 gem "zeus", require: false
 gem "fssm"
-gem "pygments.rb"
+gem "rouge"
 gem "redcarpet"
 gem "yard"
 gem "spring"
diff --git a/gemfiles/rails_6_0.gemfile.lock b/gemfiles/rails_6_0.gemfile.lock
index f3b3a2c57..e75a49623 100644
--- a/gemfiles/rails_6_0.gemfile.lock
+++ b/gemfiles/rails_6_0.gemfile.lock
@@ -107,7 +107,6 @@ GEM
     mini_portile2 (2.4.0)
     minitest (5.13.0)
     msgpack (1.3.1)
-    multi_json (1.14.1)
     nio4r (2.5.2)
     nokogiri (1.10.7)
       mini_portile2 (~> 2.4.0)
@@ -124,8 +123,6 @@ GEM
     public_suffix (4.0.1)
     puma (4.3.1)
       nio4r (~> 2.0)
-    pygments.rb (1.2.1)
-      multi_json (>= 1.0.0)
     rack (2.2.2)
     rack-test (1.1.0)
       rack (>= 1.0, < 3)
@@ -167,6 +164,7 @@ GEM
     redcarpet (3.5.0)
     regexp_parser (1.6.0)
     rexml (3.2.4)
+    rouge (3.22.0)
     rspec (3.9.0)
       rspec-core (~> 3.9.0)
       rspec-expectations (~> 3.9.0)
@@ -273,11 +271,11 @@ DEPENDENCIES
   pry
   pry-byebug
   puma (~> 4.1)
-  pygments.rb
   rails (= 6.0.2.1)
   rails-controller-testing (>= 1.0.1)
   rake (= 13.0.1)
   redcarpet
+  rouge
   rspec (~> 3.9)
   rspec-rails (~> 3.9)
   rubocop