A compound represented by the formula: its pharmaceutically acceptable salt, or a solvate thereof, wherein Ring A is aromatic carbocycle or aromatic heterocycle, Z is -NR 5 -, -O- or -S-, R 5 is hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted alkyloxycarbonyl or substituted or unsubstituted acyl, R 1 is hydrogen, halogen, hydroxy, cyano, nitro, carboxy, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted alkyloxy, substituted or unsubstituted aryloxy, substituted or unsubstituted heteroaryloxy, substituted or unsubstituted cycloalkyloxy, substituted or unsubstituted cycloalkenyloxy, substituted or unsubstituted heterocyclyloxy, substituted or unsubstituted alkylthio, substituted or unsubstituted arylthio, substituted or unsubstituted heteroarylthio, substituted or unsubstituted cycloalkylthio, substituted or unsubstituted cycloalkenylthio, substituted or unsubstituted heterocyclylthio, substituted or unsubstituted alkylsulfonyl, substituted or unsubstituted arylsulfonyl, substituted or unsubstituted heteroarylsulfonyl, substituted or unsubstituted cycloalkylsulfonyl, substituted or unsubstituted cycloalkenylsulfonyl, substituted or unsubstituted heterocyclylsulfonyl, substituted or unsubstituted acyl, substituted or unsubstituted carbamoyl or substituted or unsubstituted amino, R 2 and R 3 are each independently hydrogen, halogen, hydroxy, cyano, nitro, carboxy, substituted or unsubstituted alkyl or substituted or unsubstituted alkyloxy, R 2 and R 3 taken together may form oxo, R 4 is a group represented by the formula: -(CR 6 R 7)n-R 8, wherein R 6 and R 7 are each independently hydrogen, halogen, hydroxy, carboxy, substituted or unsubstituted alkyl or substituted or unsubstituted alkyloxy, R 6 and R 7 taken together with the adjacent carbon atom to which they are attached may form a substituted or unsubstituted ring, n is an integer of 0 to 3, R 8 is carboxy, cyano, substituted or unsubstituted alkyl, substituted or unsubstituted acyl (with the proviso that n is not 0 when R 8 is substituted or unsubstituted acyl), substituted or unsubstituted alkyloxycarbonyl, substituted or unsubstituted alkylsulfonyl, substituted or unsubstituted carbamoyl, substituted or unsubstituted amino, substituted or unsubstituted carbamoyloxy or substituted or unsubstituted alkyloxy, R x is halogen, hydroxy, cyano, nitro, carboxy, substituted or unsubstituted alkyl, substituted or unsubstituted alkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted heterocyclyl, substituted or unsubstituted alkyloxy, substituted or unsubstituted aryloxy, substituted or unsubstituted heteroaryloxy, substituted or unsubstituted cycloalkyloxy, substituted or unsubstituted cycloalkenyloxy, substituted or unsubstituted heterocyclyloxy, substituted or unsubstituted alkylthio, substituted or unsubstituted arylthio, substituted or unsubstituted heteroarylthio, substituted or unsubstituted cycloalkylthio, substituted or unsubstituted cycloalkenylthio, substituted or unsubstituted heterocyclylthio, substituted or unsubstituted alkylsulfonyl, substituted or unsubstituted arylsulfonyl, substituted or unsubstituted heteroarylsulfonyl, substituted or unsubstituted cycloalkylsulfonyl, substituted or unsubstituted cycloalkenylsulfonyl, substituted or unsubstituted heterocyclylsulfonyl, substituted or unsubstituted acyl, substituted or unsubstituted carbamoyl or substituted or unsubstituted amino, m is an integer of 0 to 3, with the proviso that the compounds wherein Z is -NR 5 -, n is 0 and R 8 is substituted or unsubstituted amino and the compounds shown as follows are excluded: