To provide a skin external agent that searches a compound having both an interaction such as stability, of the external preparation base, in addition to a good whitening effect, containing the compound. External preparation for skin containing a compound represented by the following general formula (1). (Wherein, R. Is an alkyl group having 1 to 8 carbon atoms)良好な美白作用に加えて安定性、外用剤基剤との相互作用等を併せ持つ化合物を探索し、当該化合物を含有する皮膚外用剤を提供する。下記一般式(1)で表される化合物を含有する皮膚外用剤。(式中、Rは炭素数1~8のアルキル基である。)