The method for producing porous resin microparticle of this invention contains the steps of: a step of heating a biodegradable polyester thermoplastic resin at a temperature of 80℃ or more and 200℃ or less in a glycol ether solvent to obtain a solution, and a step of cooling down the solution to precipitate the polyester thermoplastic resin as porous resin nanoparticle.本發明之多孔質樹脂微粒子的製造方法,其包含下列步驟:將具有生物分解性的聚酯系熱塑性樹脂在二醇醚系溶劑中於80℃以上200℃以下的溫度加熱而得到溶液之步驟、以及藉由使前述溶液冷卻而使前述聚酯系熱塑性樹脂作為多孔質樹脂微粒子析出之步驟。本案圖式僅表示光散射指數之測定法概要圖及多孔質樹脂微粒子之照片,不足以代表本案申請專利範圍所請發明之技術特徵,故本案無指定代表圖。
