The present invention relates to a therapeutic agent for diabetes with sulfonylurea secondary failure, which contains a GPR40 agonist. According to the present invention, a therapeutic agent for diabetes with sulfonylurea secondary failure that affords a superior insulin secretion effect and a superior hypoglycemic effect even in diabetic patients for whom a sulfonylurea compound or a fast-acting insulin secretagogue fails to provide an insulin secretion effect and therefore, fails to provide a sufficient hypoglycemic effect can be provided.