The present invention provides a raw material for cosmetic and an oil-in-water emulsion cosmetic using a core-corona type polymer particle which is excellent in emulsion stability and feeling in use.The raw material for cosmetic comprises a core-corona type polymer particle dispersion which is obtained by bringing a polyethylene oxide macromonomer represented by general formula (1) and one or two or more hydrophobic monomers represented by the general formulas (2) to (3) into radical polymerization at the following conditions (A) to (D).本發明提供一種使用乳化安定性及使用感優異之芯-冕型聚合物粒子之化妝料用原料及水中油型乳化化妝料。本發明之化妝料用原料係由通式(1)表示之聚環氧乙烷巨分子單體與通式(2)至(3)表示之疏水性單體的1種或2種以上在下述(A)至(D)的條件下進行自由基聚合而得到之芯-冕型聚合物粒子分散液所構成。
