An oil-in-water emulsified sunblock cosmetic has excellent feeling when used and maintains a high ultraviolet-ray protective effect even upon contact with water or sweat. The oil-in-water emulsified sunblock cosmetic contains an (A) ultraviolet-ray protective agent and a (B) fatty acid forming a solid at room temperature, the cosmetic is characterized in that 51% or less of the fatty acid is neutralized, and the formulation ratio ((A)/(B) of the (A) ultraviolet-ray protective agent to the (B) fatty acid is in the range of at least 0.1 and less than 10.0. The cosmetic exhibits the unprecedented and surprising property of contact with water causing an improvement to the ultraviolet-ray protective ability. It is preferable for the cosmetic to contain an (C) oily component having IOB of 0.5 or higher.