A composition for optical stereolithography, comprising a cationic polymerizable epoxy resin that is a novolac epoxy resin and/or an epoxy resin having a structure represented by the following formula (in the formula, n represents an integer of 1 or more), or the following formula (in the formula, n represents an integer of 1 or more); a cationic polymerizable compound being other than the component and having a glycidyl ether structure; a radical polymerizable compound having a methacrylic group and/or an acrylic group; a styrene-containing copolymer resin that is a copolymer resin of styrene and maleic anhydride, being the copolymer resin in which the repeating unit of the maleic anhydride is half-esterified by ring-opening to form ester and acid, and/or that is a copolymer resin of styrene and methacrylic acid or acrylic acid; a cationic polymerization initiator which is a sulfonium compound or a bis(alkylphenyl)iodonium compound; a radical polymerization initiator; and a sensitizer, wherein the composition for optical stereolithography contains: 5 to 50% by mass of the cationic polymerizable epoxy resin of the component, 5 to 70% by mass of the cationic polymerizable compound of the component, 5 to 50% by mass of the radical polymerizable compound of the component, 1 to 30% by mass of the styrene-containing copolymer resin of the component, 0.1 to 20% by mass of the cationic polymerization initiator of the component, 0.1 to 20% by mass of the radical polymerization initiator of the component, and 0.05 to 5.0% by mass of the sensitizer of the component. a cationic polymerizable epoxy resin that is a novolac epoxy resin and/or an epoxy resin having a structure represented by the following formula (in the formula, n represents an integer of 1 or more), or the following formula (in the formula, n represents an integer of 1 or more); a cationic polymerizable compound being other than the component and having a glycidyl ether structure; a radical polymerizable compound having a methacrylic group and/or an acrylic group; a styrene-containing copolymer resin that is a copolymer resin of styrene and maleic anhydride, being the copolymer resin in which the repeating unit of the maleic anhydride is half-esterified by ring-opening to form ester and acid, and/or that is a copolymer resin of styrene and methacrylic acid or acrylic acid; a cationic polymerization initiator which is a sulfonium compound or a bis(alkylphenyl)iodonium compound; a radical polymerization initiator; and a sensitizer, wherein the composition for optical stereolithography contains: 5 to 50% by mass of the cationic polymerizable epoxy resin of the component, 5 to 70% by mass of the cationic polymerizable compound of the component, 5 to 50% by mass of the radical polymerizable compound of the component, 1 to 30% by mass of the styrene-containing copolymer resin of the component, 0.1 to 20% by mass of the cationic polymerization initiator of the component, 0.1 to 20% by mass of the radical polymerization initiator of the component, and 0.05 to 5.0% by mass of the sensitizer of the component. 5 to 50% by mass of the cationic polymerizable epoxy resin of the component, 5 to 70% by mass of the cationic polymerizable compound of the component, 5 to 50% by mass of the radical polymerizable compound of the component, 1 to 30% by mass of the styrene-containing copolymer resin of the component, 0.1 to 20% by mass of the cationic polymerization initiator of the component, 0.1 to 20% by mass of the radical polymerization initiator of the component, and 0.05 to 5.0% by mass of the sensitizer of the component.