The invention relates to a whitening agent that makes effective use of camu camu seeds, which have conventionally been discarded, and that has high safety and whitening effect useful in cosmetics and the like, as well as skin preparations for external use and cosmetics containing the whitening agent. The whitening agent of the present invention contains camu camu seed extract as an active component, and the skin preparations for external use and cosmetics of the present invention contain the whitening agent.