A compound represented by the general formula or salts thereof, [wherein R 1 denotes a (C 1 -C 6)alkyl group, R 2 denotes a hydrogen atom, R 3 denotes a hydrogen atom; a (C 1 -C 6)alkyl group; or a (C 3 -C 6)cycloalkyl group, R 4 denotes a (C 1 -C 6)alkyl group; a (C 2 -C 6)alkenyl group; a (C 2 -C 6)alkynyl group; a (C 3 -C 6)cycloalkyl group; a (C 1 -C 6)alkoxy group; a halo(C 1 -C 6)alkyl group; R a (R b)N group (in the formula, each of R a and R b independently denotes a hydrogen atom, (C 1 -C 6)alkyl group, (C 3 -C 6)cycloalkyl group, (C 3 -C 6)cycloalkyl (C 1 -C 6)alkyl group, phenyl group, (C 1 -C 6)alkylcarbonyl group or phenylcarbonyl group); an aryl group; an aryl group having on the ring one to eight substituents each independently selected from the group consisting of a halogen atom, cyano group, nitro group, (C 1 -C 6)alkyl group, (C 1 -C 6)alkoxy group, (C 3 -C 6)cycloalkyl group, halo(C 1 -C 6)alkyl group, halo(C 1 -C 6)alkoxy group, halo(C 3 -C 6)cycloalkyl group, (C 1 -C 6)alkylthio group, (C 1- C 6)alkylsulfinyl group, (C 1 -C 6)alkylsulfonyl group, halo(C 1 -C 6)alkylthio group, halo(C 1 -C 6)alkylsulfinyl group and halo(C 1 -C 6)alkylsulfonyl group; a heteroaryl group; an aryl(C 1 -C 6)alkyl group; a (C 1 -C 6)alkyl group having on the chain one to three substituents each independently selected from the group consisting of a cyano group, (C 1 -C 6)alkoxy group, R a (R b)N group (in the formula, R a and R b are the same as above), (C 1 -C 6)alkylthio group, (C 1- C 6)alkylsulfinyl group and (C 1 -C 6)alkylsulfonyl group; or a 3- to 6-membered non-aromatic heterocyclic group having on the ring one or two oxygen atoms, each of X 1, X 2, X 3 and X 4 independently denotes a hydrogen atom; a halogen atom; a (C 1 -C 6)alkyl group; a (C 1 -C 6)alkoxy group; a (C 1 -C 6)alkylthio group; a (C 1- C 6)alkylsulfinyl group; or a (C 1 -C 6)alkylsulfonyl group, and Y denotes oxygen atom; or sulfur atom.]. R 1 denotes a (C 1 -C 6)alkyl group, R 2 denotes a hydrogen atom, R 3 denotes a hydrogen atom; a (C 1 -C 6)alkyl group; or a (C 3 -C 6)cycloalkyl group, a hydrogen atom; a (C 1 -C 6)alkyl group; or a (C 3 -C 6)cycloalkyl group, R 4 denotes a (C 1 -C 6)alkyl group; a (C 2 -C 6)alkenyl group; a (C 2 -C 6)alkynyl group; a (C 3 -C 6)cycloalkyl group; a (C 1 -C 6)alkoxy group; a halo(C 1 -C 6)alkyl group; R a (R b)N group (in the formula, each of R a and R b independently denotes a hydrogen atom, (C 1 -C 6)alkyl group, (C 3 -C 6)cycloalkyl group, (C 3 -C 6)cycloalkyl (C 1 -C 6)alkyl group, phenyl group, (C 1 -C 6)alkylcarbonyl group or phenylcarbonyl group); an aryl group; an aryl group having on the ring one to eight substituents each independently selected from the group consisting of a halogen atom, cyano group, nitro group, (C 1 -C 6)alkyl group, (C 1 -C 6)alkoxy group, (C 3 -C 6)cycloalkyl group, halo(C 1 -C 6)alkyl group, halo(C 1 -C 6)alkoxy group, halo(C 3 -C 6)cycloalkyl group, (C 1 -C 6)alkylthio group, (C 1- C 6)alkylsulfinyl group, (C 1 -C 6)alkylsulfonyl group, halo(C 1 -C 6)alkylthio group, halo(C 1 -C 6)alkylsulfinyl group and halo(C 1 -C 6)alkylsulfonyl group; a heteroaryl group; an aryl(C 1 -C 6)alkyl group; a (C 1 -C 6)alkyl group having on the chain one to three substituents each independently selected from the group consisting of a cyano group, (C 1 -C 6)alkoxy group, R a (R b)N group (in the formula, R a and R b are the same as above), (C 1 -C 6)alkylthio group, (C 1- C 6)alkylsulfinyl group and (C 1 -C 6)alkylsulfonyl group; or a 3- to 6-membered non-aromatic heterocyclic group having on the ring one or two oxygen atoms, a (C 1 -C 6)alkyl group; a (C 2 -C 6)alkenyl group; a (C 2 -C 6)alkynyl group; a (C 3 -C 6)cycloalkyl group; a (C 1 -C 6)alkoxy group; a halo(C 1 -C 6)alkyl group; R a (R b)N group (in the formula, each of R a and R b independently denotes a hydrogen atom, (C 1 -C 6)alkyl group, (C 3 -C 6)cycloalkyl group, (C 3 -C 6)cycloalkyl (C 1 -C 6)alkyl group, phenyl group, (C 1 -C 6)alkylcarbonyl group or phenylcarbonyl group); an aryl group; an aryl group having on the ring one to eight substituents each independently selected from the group consisting of a halogen atom, cyano group, nitro group, (C 1 -C 6)alkyl group, (C 1 -C 6)alkoxy group, (C 3 -C 6)cycloalkyl group, halo(C 1 -C 6)alkyl group, halo(C 1 -C 6)alkoxy group, halo(C 3 -C 6)cycloalkyl group, (C 1 -C 6)alkylthio group, (C 1- C 6)alkylsulfinyl group, (C 1 -C 6)alkylsulfonyl group, halo(C 1 -C 6)alkylthio group, halo(C 1 -C 6)alkylsulfinyl group and halo(C 1 -C 6)alkylsulfonyl group; a heteroaryl group; an aryl(C 1 -C 6)alkyl group; a (C 1 -C 6)alkyl group having on the chain one to three substituents each independently selected from the group consisting of a cyano group, (C 1 -C 6)alkoxy group, R a (R b)N group (in the formula, R a and R b are the same as above), (C 1 -C 6)alkylthio group, (C 1- C 6)alkylsulfinyl group and (C 1 -C 6)alkylsulfonyl group; or a 3- to 6-membered non-aromatic heterocyclic group having on the ring one or two oxygen atoms, each of X 1, X 2, X 3 and X 4 independently denotes a hydrogen atom; a halogen atom; a (C 1 -C 6)alkyl group; a (C 1 -C 6)alkoxy group; a (C 1 -C 6)alkylthio group; a (C 1- C 6)alkylsulfinyl group; or a (C 1 -C 6)alkylsulfonyl group, and a hydrogen atom; a halogen atom; a (C 1 -C 6)alkyl group; a (C 1 -C 6)alkoxy group; a (C 1 -C 6)alkylthio group; a (C 1- C 6)alkylsulfinyl group; or a (C 1 -C 6)alkylsulfonyl group, and Y denotes oxygen atom; or sulfur atom.].