A diazepine derivative having the following formula or a pharmacologically acceptable salt thereof: wherein each of R 1 and R 2 independently is hydrogen, a C 1-8 alkyl group, a C 2-8 alkenyl group, a C 1-8 alkoxy group, a C 1-8 alkyl group having one to three halogen atoms, a C 1-8 alkoxy group having one to three halogen atoms, a halogen atom, hydroxyl, nitro, cyano, amino, a C 1-8 alkylamino group, a C 2-8 dialkylamino group, a C 2-8 acylamino group, a C 2-8 acylamino group having one to three halogen atoms, a C 1-8 alkylsulfonylamino group, carboxyl, a C 2-8 acyl group, an alkoxycarbonyl group comprising a C 1-8 alkoxy moiety, carbamoyl, a C 1-8 alkylthio group, a C 1-8 alkylsulfinyl group, a C 1-8 alkylsulfonyl group, or sulfamoyl, and each of R 1 and R 2 optionally is the same or different two or more substituents attached to the ring; R 3 is hydrogen, a C 1-8 alkyl group, a C 2-8 alkenyl group, a C 2-8 acyl group, a C 1-8 alkyl group having one to three halogen atoms, or a C 1-3 alkyl group having phenyl; each of R 4 and R 5 independently is hydrogen, a C 1-8 alkyl group, a C 1-8 alkyl group having one to three halogen atoms, a halogen atom, hydroxyl, nitro, cyano, amino, or a C 1-3 alkyl group having phenyl; R 6 is hydrogen, a C 1-8 alkyl group, a C 2-8 alkenyl group, a C 1-8 alkoxy group, a C 1-8 alkyl group having one to three halogen atoms, a C 1-8 alkoxy group having one to three halogen atoms, a halogen atom, hydroxyl, nitro, cyano, amino, a C 1-8 alkylamino group, a C 2-8 dialkylamino group, a C 2-8 acylamino group, a C 2-8 acylamino group having one to three halogen atoms, a C 1-8 alkylsulfonylamino group, carboxyl, a C 2-8 acyl group, an alkoxycarbonyl group comprising a C 1-8 alkoxy moiety, carbamoyl, a C 1-8 alkylthio group, a C 1-8 alkylsulfinyl group, a C 1-8 alkylsulfonyl group, a C 3-8 alkoxycarbonylamino group, sulfamoyl, phenyl optionally having one or more substituents, or a heterocyclic group optionally having one or more substituents, and R 6 optionally is the same or different two or more substituents attached to the ring; the ring shown below is a five-membered to eight-membered non-aromatic ring optionally comprising one or two heteroatoms selected from N, S, and O, and being condensed with the benzene ring at the positions of 1 and 2 of the benzene ring; the ring shown below is an aromatic ring selected from the group consisting of benzene ring, naphthalene ring, thiophene ring, pyridine ring, pyrimidine ring, indole ring, indazole ring, benzotriazole ring, benzisoxazole ring, benzimidazole ring, and quinoline ring; Z is O or S; when X is N, Y is C=O or C=S, and the double line consisting of a solid line and a broken line is a single bond; and when X is C, Y is N, and the double line consisting of a solid line and a broken line is a double bond. wherein each of R 1 and R 2 independently is hydrogen, a C 1-8 alkyl group, a C 2-8 alkenyl group, a C 1-8 alkoxy group, a C 1-8 alkyl group having one to three halogen atoms, a C 1-8 alkoxy group having one to three halogen atoms, a halogen atom, hydroxyl, nitro, cyano, amino, a C 1-8 alkylamino group, a C 2-8 dialkylamino group, a C 2-8 acylamino group, a C 2-8 acylamino group having one to three halogen atoms, a C 1-8 alkylsulfonylamino group, carboxyl, a C 2-8 acyl group, an alkoxycarbonyl group comprising a C 1-8 alkoxy moiety, carbamoyl, a C 1-8 alkylthio group, a C 1-8 alkylsulfinyl group, a C 1-8 alkylsulfonyl group, or sulfamoyl, and each of R 1 and R 2 optionally is the same or different two or more substituents attached to the ring; R 3 is hydrogen, a C 1-8 alkyl group, a C 2-8 alkenyl group, a C 2-8 acyl group, a C 1-8 alkyl group having one to three halogen atoms, or a C 1-3 alkyl group having phenyl; each of R 4 and R 5 independently is hydrogen, a C 1-8 alkyl group, a C 1-8 alkyl group having one to three halogen atoms, a halogen atom, hydroxyl, nitro, cyano, amino, or a C 1-3 alkyl group having phenyl; R 6 is hydrogen, a C 1-8 alkyl group, a C 2-8 alkenyl group, a C 1-8 alkoxy group, a C 1-8 alkyl group having one to three halogen atoms, a C 1-8 alkoxy group having one to three halogen atoms, a halogen atom, hydroxyl, nitro, cyano, amino, a C 1-8 alkylamino group, a C 2-8 dialkylamino group, a C 2-8 acylamino group, a C 2-8 acylamino group having one to three halogen atoms, a C 1-8 alkylsulfonylamino group, carboxyl, a C 2-8 acyl group, an alkoxycarbonyl group comprising a C 1-8 alkoxy moiety, carbamoyl, a C 1-8 alkylthio group, a C 1-8 alkylsulfinyl group, a C 1-8 alkylsulfonyl group, a C 3-8 alkoxycarbonylamino group, sulfamoyl, phenyl optionally having one or more substituents, or a heterocyclic group optionally having one or more substituents, and R 6 optionally is the same or different two or more substituents attached to the ring; the ring shown below is a five-membered to eight-membered non-aromatic ring optionally comprising one or two heteroatoms selected from N, S, and O, and being condensed with the benzene ring at the positions of 1 and 2 of the benzene ring; the ring shown below is an aromatic ring selected from the group consisting of benzene ring, naphthalene ring, thiophene ring, pyridine ring, pyrimidine ring, indole ring, indazole ring, benzotriazole ring, benzisoxazole ring, benzimidazole ring, and quinoline ring; Z is O or S; when X is N, Y is C=O or C=S, and the double line consisting of a solid line and a broken line is a single bond; and when X is C, Y is N, and the double line consisting of a solid line and a broken line is a double bond.