The present invention provides a compound which has metastin receptor antagonist activity and is useful for preventing and treating hormone-dependent cancer, benign prostatomegaly, endometriosis, precocious puberty, uterine myoma or the like. More specifically, the present invention provides a compound, represented by the formula: or a salt thereof, a prodrug thereof, and a pharmaceutical agent containing the same; wherein Ring A represents a 5- to 8-membered homocyclic or heterocyclic group optionally having a substituent other than formula —X-R1 wherein X represents a bond or a spacer, and R1 represents optionally substituted amino or an optionally substituted nitrogen-containing heterocyclic group; Ring B represents an optionally substituted benzene ring; R2 represents an optionally substituted homocyclic or heterocyclic group; and R3 and R4 independently represent a hydrogen atom, cyano, acyl or an optionally substituted hydrocarbon group.