[PROBLEMS] To provide a compound which can be used as a pharmaceutical agent, particularly an insulin secretion enhancer or a prophylactic/therapeutic agent for a disease associated with GPR40 such as diabetes. [MEANS FOR SOLVING PROBLEMS] It is found that an oxadiazolidinedione compound having, at the 2-position of an oxadiazolidinedione ring, a substituent (e.g., a benzyl) bound to a cyclic group through a linker, or a pharmaceutically acceptable salt thereof has an excellent GPR40 agonistic activity. The oxadiazolidinedione compound shows an excellent insulin secretion enhancing effect and an excellent anti-hyperglycemic effect, and therefore is useful as an insulin secretion enhancer or a prophylactic/therapeutic agent for diabetes.
