A composition for optical stereolithography, comprising (A) a cationic polymerizable epoxy resin that is a novolac epoxy resin and/or an epoxy resin having a structure represented by the following formula (I) (in the formula, n represents an integer of 1 or more), or the following formula (II) (in the formula, n represents an integer of 1 or more); (B) a cationic polymerizable compound being other than the component (A) and having a glycidyl ether structure; (C) a radical polymerizable compound having a methacrylic group and/or an acrylic group; (D) 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; (E) a cationic polymerization initiator which is a sulfonium compound or a bis(alkylphenyl)iodonium compound; (F) a radical polymerization initiator; and (G) a sensitizer, wherein the composition for optical stereolithography contains: 5 to 50% by mass of the cationic polymerizable epoxy resin of the component (A), 5 to 70% by mass of the cationic polymerizable compound of the component (B), 5 to 50% by mass of the radical polymerizable compound of the component (C), 1 to 30% by mass of the styrene-containing copolymer resin of the component (D), 0.1 to 20% by mass of the cationic polymerization initiator of the component (E), 0.1 to 20% by mass of the radical polymerization initiator of the component (F), and 0.05 to 5.0% by mass of the sensitizer of the component (G). (A) a cationic polymerizable epoxy resin that is a novolac epoxy resin and/or an epoxy resin having a structure represented by the following formula (I) (in the formula, n represents an integer of 1 or more), or the following formula (II) (in the formula, n represents an integer of 1 or more); (B) a cationic polymerizable compound being other than the component (A) and having a glycidyl ether structure; (C) a radical polymerizable compound having a methacrylic group and/or an acrylic group; (D) 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; (E) a cationic polymerization initiator which is a sulfonium compound or a bis(alkylphenyl)iodonium compound; (F) a radical polymerization initiator; and (G) a sensitizer, wherein the composition for optical stereolithography contains: 5 to 50% by mass of the cationic polymerizable epoxy resin of the component (A), 5 to 70% by mass of the cationic polymerizable compound of the component (B), 5 to 50% by mass of the radical polymerizable compound of the component (C), 1 to 30% by mass of the styrene-containing copolymer resin of the component (D), 0.1 to 20% by mass of the cationic polymerization initiator of the component (E), 0.1 to 20% by mass of the radical polymerization initiator of the component (F), and 0.05 to 5.0% by mass of the sensitizer of the component (G). 5 to 50% by mass of the cationic polymerizable epoxy resin of the component (A), 5 to 70% by mass of the cationic polymerizable compound of the component (B), 5 to 50% by mass of the radical polymerizable compound of the component (C), 1 to 30% by mass of the styrene-containing copolymer resin of the component (D), 0.1 to 20% by mass of the cationic polymerization initiator of the component (E), 0.1 to 20% by mass of the radical polymerization initiator of the component (F), and 0.05 to 5.0% by mass of the sensitizer of the component (G). <EOS>