diff --git a/mrblib/10error.rb b/mrblib/10error.rb
index aa9da91bb..431f77809 100644
--- a/mrblib/10error.rb
+++ b/mrblib/10error.rb
@@ -1,3 +1,16 @@
+class Exception
+  ##
+  # call-seq:
+  #   exception.message   ->  string
+  #
+  # Returns the result of invoking <code>exception.to_s</code>.
+  # Normally this returns the exception's message or name.
+  #
+  def message
+    to_s
+  end
+end
+
 # ISO 15.2.24
 class ArgumentError < StandardError
 end
diff --git a/src/error.c b/src/error.c
index 46d26bece..acad904e3 100644
--- a/src/error.c
+++ b/src/error.c
@@ -136,20 +136,6 @@ exc_to_s(mrb_state *mrb, mrb_value exc)
   return mesg;
 }
 
-/*
- * call-seq:
- *   exception.message   ->  string
- *
- * Returns the result of invoking <code>exception.to_s</code>.
- * Normally this returns the exception's message or name.
- */
-
-static mrb_value
-exc_message(mrb_state *mrb, mrb_value exc)
-{
-  return mrb_funcall_id(mrb, exc, MRB_SYM(to_s), 0);
-}
-
 /*
  * call-seq:
  *   exception.inspect   -> string
@@ -667,7 +653,6 @@ mrb_init_exception(mrb_state *mrb)
   mrb_define_method(mrb, exception, "exception",       exc_exception,     MRB_ARGS_OPT(1));
   mrb_define_method(mrb, exception, "initialize",      exc_initialize,    MRB_ARGS_OPT(1));
   mrb_define_method(mrb, exception, "to_s",            exc_to_s,          MRB_ARGS_NONE());
-  mrb_define_method(mrb, exception, "message",         exc_message,       MRB_ARGS_NONE());
   mrb_define_method(mrb, exception, "inspect",         mrb_exc_inspect,   MRB_ARGS_NONE());
   mrb_define_method(mrb, exception, "backtrace",       mrb_exc_backtrace, MRB_ARGS_NONE());
   mrb_define_method(mrb, exception, "set_backtrace",   exc_set_backtrace, MRB_ARGS_REQ(1));