Disclosed is an oil-in-water emulsion base which is stable even when ethanol in an amount of 50% by mass or less is blended therein and which exhibits excellent water resistance after being applied to the skin or the like. Specifically disclosed is an oil-in-water emulsified cosmetic composition which is characterized by containing (A) 0.1-10% by mass of a polyether-modified silicone having an HLB(Si) of 5-10, (B) 5-50% by mass of ethanol, (C) 0.01-3% by mass of a hydrophilic thickening agent and (D) 0.1-15% by mass of a polyol. Preferably, the oil-in-water emulsified cosmetic composition additionally contains a UV absorbent, thereby forming a sunscreen cosmetic composition.