A heterocyclic compound or a salt thereof represented by the formula (1): in which R2 represents a hydrogen atom or a C1-C6 alkyl group； A represents a C1-C6 alkylene group or a C2-C6 alkenylene group； and R1 represents a heterocyclic group selected from a heterocyclic group fused to benzene having 1 to 4 heteroatoms selected from the group consisting of a nitrogen atom, an oxygen atom and a sulfur atom, and which is selected from the group consisting in (1) a tetrahydroquinoxalinyl group, (2) a tetrahydroquinazolinyl group, (3) a dihydroquinazolinyl group, (4) an indolinyl group, (5) an indolyl group, (6) an isoindolinyl group, (7) a benzimidazolyl group, (8) a dihydrobenzimidazolyl group, (9) a tetrahydrobenzazepinyl group, (10) a tetrahydrobenzodiazepinyl group, (11) a hexahydrobenzazocinyl group, (12) a dihydrobenzoxazinyl group, (13) a dihydrobenzoxazolyl group, (14) a benzyl group, (14) a bencis group 15) a benzoxadiazolyl group, (16) a tetrahydrobenzoxazepinyl group, (17) a dihydrobenzothiazinyl group, (18) a benzothiazolyl group, (19) a benzoxatiolyl group, (20) a chromenyl group, (21) a dihydrobenzofuryl group, (22 ) a carbazolyl group, (23) a dibenzofuryl group and (24) a quinoxalinyl group, in which at least one group selected from the group consisting of the following groups (1) to (66) may be present as a substituent in the represented heterocyclic group by R1: (1) a C1-C6 alkyl group, (2) a C2-C6 alkenyl group, (3) a halogen substituted C1-C6 alkyl group, (4) a C1-C6 alkoxy group, (5) a aryloxy group, (6) a C1-C6 alkylthio group, (7) a halogen-substituted C1-C6 alkoxy group, (8) a hydroxyl group, (9) a protected hydroxyl group, (10) a C1-C6 hydroxyalkyl group , (11) a protected C1-C6 hydroxyalkyl group, (12) a halogen atom, (13) a cyano group, (14) an aryl group, (15) a nitro group, (16) an amino group, (17 ) an amino group having one or more groups selected from the group consisting of a C1-C6 alkyl group, a C1-C6 alkanoyl group, a C1-C6 alkoxycarbony
