Disclosed is an agent for skin external preparation which is hardly reduced in viscosity even when stored for a long period under extreme high temperature storage conditions and is therefore stable. The preparation is in an emulsion form, and comprises (1) an alginic acid polyol ester having an esterification degree ranging from 75 to 95% (e.g., alginic acid propylene glycol ester) and/or a salt thereof (2) a polyvalent metal ion (e.g., a calcium ion) and (3) a 4-alkylresolcinol (e.g., 4-n-butylresolcinol) and/or a salt thereof.
