The purpose of the present invention is to provide a method for evaluating a cosmetic, which enables the development of a cosmetic that can make a skin beautiful and healthy. The purpose can be achieved by provid-ing a method for evaluating a skin-improving effect of a cosmetic applied onto a skin employing, as a measure, the change in thickness of a horny cell layer between a point of time at which the skin is moisturized and a point of time at which the skin is dried after the moisturization.