diff --git a/lib/uri/rfc2396_parser.rb b/lib/uri/rfc2396_parser.rb
index cefd126..ddbf74e 100644
--- a/lib/uri/rfc2396_parser.rb
+++ b/lib/uri/rfc2396_parser.rb
@@ -320,14 +320,13 @@ def unescape(str, escaped = @regexp[:ESCAPED])
       str.gsub(escaped) { [$&[1, 2]].pack('H2').force_encoding(enc) }
     end
 
-    TO_S = Kernel.instance_method(:to_s) # :nodoc:
-    if TO_S.respond_to?(:bind_call)
+    if UnboundMethod.method_defined?(:bind_call)
       def inspect # :nodoc:
-        TO_S.bind_call(self)
+        Kernel.instance_method(:to_s).bind_call(self)
       end
     else
       def inspect # :nodoc:
-        TO_S.bind(self).call
+        Kernel.instance_method(:to_s).bind(self).call
       end
     end
 
diff --git a/lib/uri/rfc3986_parser.rb b/lib/uri/rfc3986_parser.rb
index 0b5f0c4..4bd55f3 100644
--- a/lib/uri/rfc3986_parser.rb
+++ b/lib/uri/rfc3986_parser.rb
@@ -164,14 +164,13 @@ def unescape(str, escaped = nil) # :nodoc:
       escaped ? RFC2396_PARSER.unescape(str, escaped) : RFC2396_PARSER.unescape(str)
     end
 
-    @@to_s = Kernel.instance_method(:to_s)
-    if @@to_s.respond_to?(:bind_call)
+    if UnboundMethod.method_defined?(:bind_call)
       def inspect
-        @@to_s.bind_call(self)
+        Kernel.instance_method(:to_s).bind_call(self)
       end
     else
       def inspect
-        @@to_s.bind(self).call
+        Kernel.instance_method(:to_s).bind(self).call
       end
     end
 
diff --git a/test/uri/test_parser.rb b/test/uri/test_parser.rb
index c14824f..0917beb 100644
--- a/test/uri/test_parser.rb
+++ b/test/uri/test_parser.rb
@@ -12,6 +12,16 @@ def test_inspect
     assert_match(/URI::RFC3986_Parser/, URI::Parser.new.inspect)
   end
 
+  def test_inspect_in_ractor
+    return unless defined?(Ractor)
+    assert_ractor(<<~RUBY, require: 'uri')
+      r = Ractor.new { [URI::RFC3986_PARSER.inspect, URI::RFC2396_PARSER.inspect] }
+      rfc3986, rfc2396 = r.value
+      assert_match(/URI::RFC3986_Parser/, rfc3986)
+      assert_match(/URI::RFC2396_Parser/, rfc2396)
+    RUBY
+  end
+
   def test_compare
     url = 'http://a/b/c/d;p?q'
     u0 = URI.parse(url)