diff --git a/CHANGELOG.md b/CHANGELOG.md
index bb2bf49..f8290e4 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## [Unreleased]
 
+- Change owner method define from `self.calss.define_method` to `self.define_singleton_method`
+
 ## [1.1.0] - 2022-10-08
 
 - Support `module_function`
diff --git a/lib/active_method/base.rb b/lib/active_method/base.rb
index 5ae8d75..3a29f76 100644
--- a/lib/active_method/base.rb
+++ b/lib/active_method/base.rb
@@ -105,7 +105,7 @@ def __set_owner(owner)
       @__method_owner = owner
 
       instance_name = Util.snake_case(owner.class.name.split("::").last)
-      self.class.define_method instance_name do
+      self.define_singleton_method instance_name do
         @__method_owner
       end
     end