An azole derivative represented by the following general formula (I) ##STR1## (symbols in the formula have the following meanings; R.sup.1 and R.sup.2 : the same or different from each other and each represents a hydrogen atom, a lower alkyl group or a phenyl group which may be substituted with a halogen atom, A, B and D: the same or different from one another and each represents a group represented by the formula ##STR2## or a nitrogen atom, X and Y: the same or different from each other and each represents a single bond, a methylene group, an oxygen atom, a group represented by a formula S(O).sub.n, or a group represented by the formula ##STR3## R.sup.3 and R.sup.4 : the same or different from each other and each represents a hydrogen atom or a lower alkyl group, and n: 0, 1 or 2), a salt thereof, a hydrate thereof or a solvate thereof. This compound has a function to inhibit steroid 17-20 lyase and is useful as preventive and treating agents for prostatic cancer, prostatic hypertrophy, virilism, breast cancer, mastopathy, histeromyoma, and endometriosis.