Provided is a hyaluronic acid production promoter and a melanin synthesis inhibitor. The hyaluronic acid production promoter and the melanin synthesis inhibitor of the present invention each contain soybean saponin as an active ingredient. The soybean saponin is preferably soybean saponin aglycone. The soybean saponin aglycone preferably includes soyasapogenol A and/or soyasapogenol B. The hyaluronic acid production promoter and the melanin synthesis inhibitor of the present invention are each administered transdermally or orally.