Provided is a compound showing excellent antifungalactivity against Trichophyton fungus, which is a majorcausative microorganism of superficial mycosis, and higheffectiveness on diseases caused by Trichophyton fungi. Abiaryl derivative represented by the formula (I) or a saltthereof:(see formula I)wherein ring A is an optionally substituted phenyl, or anoptionally substituted 5- or 6-membered ring heteroaryl (ring Amay be further condensed to form an optionally substitutedfused ring)； Q is CH2, C=O, NH, O, S or the like； X1, X2 and X3are CR1 or N； Y is CH or N； Z is CR2b or N； R2a and R2b are eacha hydrogen atom, a halogen atom, an optionally substitutedC1-C6 alkyl group, a C1-C6 haloalkyl group or the like； R2a and R2bmay form, together with carbon atoms bonded thereto, anoptionally substituted carbocycle, or an optionally substitutedheterocycle.
