Disclosed is a compound which is useful as an AMPK activator.A compound represented by formula: or a pharmaceutically acceptable salt thereof, wherein R4 is hydrogen, or substituted or unsubstituted alkyl, R1, R2 and R3 are each independently hydrogen, halogen, hydroxy, cyano, nitro, carboxy, substituted or unsubstituted alkyl or the like, with the proviso that R1, R2 and R3 are not simultaneously hydrogen, X is a single bond, —S—, —O—, —NR5—, —C(═O)— or the like, R5 is hydrogen, or substituted or unsubstituted alkyl, Y is substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted heterocyclyl or the like.