This invention provides an inhibitor for melanin formation, which has excellent and high safety on inhibition of melanin formation. The inhibitor for melanin formation comprises a compound of formula (1) and/or pharmaceutically acceptable slats, provided that clotrimazole is excluded. wherein A1, A2 and A3 are individually hydrogen atom, optionally substituted aryl, and optionally substituted aromatic heterocyclic group； wherein at least one of A1, A2 and A3 are selected from the aryl or aromatic heterocyclic group, the sum of carbon number for A1, A2 and A3 is 6 to 50； besides, the adjacent two aryl or aromatic heterocyclic group are bound by alkyl chain or alkenyl chain or formed a ring while the two or more of A1, A2 and A3 are the aryl or aromatic heterocyclic group； m is an integral of 0 to 2； X is a hetero atom, hydrogen atom, or carbon atom； R1 and R2 are individually hydrogen atom and oxo, provided that one of R1 and R2 is an oxo, the other group does not exist； R3 is hydrogen atom or C1-8 hydrocarnons that partial hydrogen or carbon atom are optionally substituted by hetero atoms, and the amount of R3 depends on X, R3 is individual while there is more than two R3, or R3 and X form a ring while there is more than two R3, or a ring is formed while the end of R3 binds to a carbon atom of A1, A2 and A3.Винахід стосується застосування сполук загальної формули,крім клотримазолу, де сполуки, представлені загальною формулою (1), не містять імідазольне кільце, і/або їх фармакологічно прийнятних солей як інгібіторів продукування меланіну та її застосування у препараті зовнішнього застосування.
