Provided is a cosmetic agent superior in a whitening effect (including prophylaxis and removal of pigmented spot) and having high safety. In addition, a superior melanin production suppressive agent is provided. A cosmetic agent or melanin production suppressive agent comprising (A) a cysteine derivative represented by the formula (I) or a salt thereof: wherein X and Y are each independently OR 1 or NHR 2 wherein R 1 and R 2 are each independently a hydrogen atom or a C 1-22 alkyl group； Z is a hydrogen atom or a C 1-22 alkyl group； and W is a C 1-22 alkyl group, a C 1-22 alkoxy group or a C 1-22 alkylamino group, and (B) a whitening agent.
