diff --git a/lib/rggen/core/input_base/yaml_loader.rb b/lib/rggen/core/input_base/yaml_loader.rb
index 2bc109e..dde832d 100644
--- a/lib/rggen/core/input_base/yaml_loader.rb
+++ b/lib/rggen/core/input_base/yaml_loader.rb
@@ -49,10 +49,8 @@ def mapping_key?
         end
 
         class Visitor < ::Psych::Visitors::ToRuby
-          if ::Psych::VERSION >= '3.2.0'
-            def initialize(scalar_scanner, class_loader)
-              super(scalar_scanner, class_loader, symbolize_names: true)
-            end
+          def initialize(scalar_scanner, class_loader)
+            super(scalar_scanner, class_loader, symbolize_names: true)
           end
 
           def accept(node)
@@ -79,7 +77,6 @@ def override_object?(node)
         def load_yaml(file)
           parse_yaml(File.binread(file), file)
             .then { |result| to_ruby(result) }
-            .then { |result| symbolize_names(result) }
         end
 
         def parse_yaml(yaml, file)
@@ -93,20 +90,6 @@ def to_ruby(result)
           ss = ::Psych::ScalarScanner.new(cl)
           Visitor.new(ss, cl).accept(result)
         end
-
-        def symbolize_names(result)
-          return result if ::Psych::VERSION >= '3.2.0'
-
-          if result.match_class?(Hash)
-            result
-              .transform_keys!(&:to_sym)
-              .transform_values!(&method(:symbolize_names))
-          elsif result.match_class?(Array)
-            result.map! { |value| symbolize_names(value) }
-          end
-
-          result
-        end
       end
     end
   end