PROBLEM TO BE SOLVED: To provide a method for producing a porous silica-based particle having a large pore volume in spite of a small specific surface area.SOLUTION: The method for producing a porous silica-based particle comprises: a first step of preparing a silica sol including silica-based fine particles having an average particle size of more than 100 to 1,000 nm with a solid content concentration of 25 to 50 mass%； a second step of mixing the silica sol with a silicic acid solution including a silicic acid component with a solid content concentration of 1 to 40 mass% to form a slurry having a mass ratio (silica/silicic acid) of the silica-based fine particle to the silicic acid component in the range of 90/10 to 98/2； a third step of drying the slurry at 100 to 400°C within 10 minutes to obtain a dried powder； and a fourth step of screening the dried powder. The solid content concentration (in terms of silicon dioxide) of silicic acid in the slurry obtained through the second step is 1.5 to 7.0 mass%.SELECTED DRAWING: None【課題】比表面積が小さいにも関わらず、細孔容積が大きい多孔質シリカ系粒子の製造方法を提供する。【解決手段】平均粒子径１００超～１０００ｎｍのシリカ系微粒子を固形分濃度２５～５０質量％含むシリカゾルを用意する第一工程と、シリカゾルと珪酸成分を固形分濃度１～４０質量％含む珪酸溶液とを混合し、シリカ系微粒子成分と珪酸成分との質量比（シリカ／珪酸）が９０/１０～９８／２の範囲にあるスラリーを作製する第二工程と、このスラリーを、１００～４００℃、１０分以内で乾燥させ、乾燥粉体を得る第三工程と、乾燥粉体を篩分けする第四工程と、を備えており、第二工程程により得られるスラリー中の珪酸の固形分濃度（二酸化珪素換算）が１．５～７．０質量％である多孔質シリカ系粒子の製造方法。【選択図】なし
