Provided is a compound presenting high efficacy in diseases caused by Trichophyton by having excellent antifungal activity against Trichophyton, which is a major causative organism of superficial mycoses. A biaryl derivative represented by general formula (I) [in the formula, ring A represents an optionally substituted phenyl or optionally substituted 5- or 6-membered ring heteroaryl (ring A may be further condensed to form an optionally substituted fused ring)； Q is CH2, C=O, NH, O, or S, or the like； X1?X2, and X3 are CR1 or N； Y is CH or N； Z is CR2b or N； R2a and R2b are a hydrogen atom, halogen atom, optionally substituted C1-C6 alkyl group, C1-C6 haloalkyl group, or the like； R2a and R2b, together with the carbon atoms to which they are attached, may form an optionally substituted carbon ring or an optionally substituted heterocycle] or a salt thereof.
