Provided is an azole derivative superior in disease-controlling activity contained as an active ingredient in agricultural or horticultural chemical agents.The azole derivative according to the present invention is represented by the following General Formula (I): (in Formula (I), R1 represents an unsubstituted or substituted C1-C6-alkyl group; R2 represents a carbonyl group-containing functional group, wherein the carbon atom in the carbonyl group is bound to the carbon atom in the cyclopentane ring substituted with R1 and to a hydrogen atom, a hydroxyl group, R3, OR3, or NR3R4; R3 and R4 each represent a C1-C6-alkyl group, a C2-C6-alkenyl group, or a C2-C6-alkynyl group; Y represents a halogen atom, a C1-C4-alkyl group, a C1-C4-haloalkyl group, a C1-C4-alkoxy group, a C1-C4-haloalkoxy group, a phenyl group, a cyano group, or a nitro group; m is 0 to 5; and A represents a nitrogen atom or a methine group).