A compound represented by the formula: wherein R 1 is a phenyl group, a C 5-6 cycloalkyl group, a 5- or 6-membered monocyclic non-aromatic heterocyclic group or a 5- or 6-membered monocyclic aromatic heterocyclic group, each of which is optionally substituted by 1 to 3 substituents selected from (i) a halogen atom, (ii) a cyano group, (iii) a hydroxy group, (iv) a C 1-6 alkyl group optionally substituted by 1 to 3 hydroxy groups, and (v) a C 1-6 alkoxy group, or a C 1-6 alkyl group optionally substituted by 1 to 3 substituents selected from (i) a hydroxy group, and (ii) a 3- to 14-membered non-aromatic heterocyclic group; R 2 is a hydrogen atom, a halogen atom, or a C 1-6 alkyl group; R 3 is a hydrogen atom, a halogen atom, a cyano group, a C 1-6 alkyl group optionally substituted by 1 to 3 halogen atoms, a C 1-6 alkoxy group, or a C 3-6 cycloalkyl group; R 4 is a halogen atom, a cyano group, a C 1-6 alkyl group, a C 1-6 alkoxy group optionally substituted by 1 to 3 halogen atoms, a carbamoyl group, a mono- or di-C 1-6 alkyl-carbamoyl group, or a 5- or 6-membered monocyclic aromatic heterocyclic group optionally substituted by 1 to 3 C 1-6 alkyl groups; and Ring A is a 6-membered aromatic ring optionally further substituted by 1 to 3 substituents, in addition to R 4, selected from (a) a halogen atom, (b) a C 1-6 alkyl group, and (c) a C 1-6 alkoxy group, or a pharmaceutically acceptable salt thereof. R 1 is a phenyl group, a C 5-6 cycloalkyl group, a 5- or 6-membered monocyclic non-aromatic heterocyclic group or a 5- or 6-membered monocyclic aromatic heterocyclic group, each of which is optionally substituted by 1 to 3 substituents selected from (i) a halogen atom, (ii) a cyano group, (iii) a hydroxy group, (iv) a C 1-6 alkyl group optionally substituted by 1 to 3 hydroxy groups, and (v) a C 1-6 alkoxy group, or a C 1-6 alkyl group optionally substituted by 1 to 3 substituents selected from (i) a hydroxy group, and (ii) a 3- to 14-membered non-aromatic heterocyclic group; a phenyl group, a C 5-6 cycloalkyl group, a 5- or 6-membered monocyclic non-aromatic heterocyclic group or a 5- or 6-membered monocyclic aromatic heterocyclic group, each of which is optionally substituted by 1 to 3 substituents selected from (i) a halogen atom, (ii) a cyano group, (iii) a hydroxy group, (iv) a C 1-6 alkyl group optionally substituted by 1 to 3 hydroxy groups, and (v) a C 1-6 alkoxy group, or (i) a halogen atom, (ii) a cyano group, (iii) a hydroxy group, (iv) a C 1-6 alkyl group optionally substituted by 1 to 3 hydroxy groups, and (v) a C 1-6 alkoxy group, or a C 1-6 alkyl group optionally substituted by 1 to 3 substituents selected from (i) a hydroxy group, and (ii) a 3- to 14-membered non-aromatic heterocyclic group; (i) a hydroxy group, and (ii) a 3- to 14-membered non-aromatic heterocyclic group; R 2 is a hydrogen atom, a halogen atom, or a C 1-6 alkyl group; a hydrogen atom, a halogen atom, or a C 1-6 alkyl group; R 3 is a hydrogen atom, a halogen atom, a cyano group, a C 1-6 alkyl group optionally substituted by 1 to 3 halogen atoms, a C 1-6 alkoxy group, or a C 3-6 cycloalkyl group; a hydrogen atom, a halogen atom, a cyano group, a C 1-6 alkyl group optionally substituted by 1 to 3 halogen atoms, a C 1-6 alkoxy group, or a C 3-6 cycloalkyl group; R 4 is a halogen atom, a cyano group, a C 1-6 alkyl group, a C 1-6 alkoxy group optionally substituted by 1 to 3 halogen atoms, a carbamoyl group, a mono- or di-C 1-6 alkyl-carbamoyl group, or a 5- or 6-membered monocyclic aromatic heterocyclic group optionally substituted by 1 to 3 C 1-6 alkyl groups; and a halogen atom, a cyano group, a C 1-6 alkyl group, a C 1-6 alkoxy group optionally substituted by 1 to 3 halogen atoms, a carbamoyl group, a mono- or di-C 1-6 alkyl-carbamoyl group, or a 5- or 6-membered monocyclic aromatic heterocyclic group optionally substituted by 1 to 3 C 1-6 alkyl groups; and Ring A is a 6-membered aromatic ring optionally further substituted by 1 to 3 substituents, in addition to R 4, selected from (a) a halogen atom, (b) a C 1-6 alkyl group, and (c) a C 1-6 alkoxy group, or a pharmaceutically acceptable salt thereof. (a) a halogen atom, (b) a C 1-6 alkyl group, and (c) a C 1-6 alkoxy group,