The present invention provides core-corona type polymer particles excellent in emulsion stability and feeling in use, and a raw material for cosmetics and an oil-in-water emulsion cosmetic using the particles.The core-corona type polymer particles of the present invention are obtained by radical polymerization of a polyethylene oxide macromonomer represented by the general formula (1) and one or two or more kinds of hydrophobic monomers represented by the general formulas (2) to (3) under the conditions of (A) to (D).本發明提供一種乳化安定性及使用感優異之芯-冕型聚合物粒子、及使用該粒子之化妝料用原料及水中油型乳化化妝料。本發明之芯-冕型聚合物粒子係由通式(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(A)至(D)的條件下進行自由基聚合而得到者。
