In a triterpenic acid having hydroxyl groups, at least one of the hydroxyl groups is phosphorylated to produce a phosphorylated triterpenic acid and/or a salt thereof, thereby improving the solubility of the triterpenic acid in a preparation for external application for the skin and allowing the physiological activity of the triterpenic acid to be exerted satisfactorily. The phosphorylated triterpenic acid is preferably, for example, ursolic acid phosphate and/or a salt thereof. The preparation for external application for the skin is preferably a cosmetic, particularly preferably a quasi-drug.