A process for producing an optical material, comprising: a step of mixing di- or higher-functional thiol compounds (A) having one or more sulfide bonds and/or one or more ester bonds with an imidazole-based curing catalyst (B) to prepare a mixed solution; a step of mixing the mixed solution with an isocyanate compound (C) including at least one kind of a di- or higher-functional alicyclic isocyanate compound (c1) and/or a di- or higher-functional aliphatic isocyanate compound (c2) to prepare a polymerizable composition for optical materials; a step of injecting the polymerizable composition for optical materials into a mold; and a step of polymerization-curing the polymerizable composition for optical materials in the mold; wherein the imidazole-based curing catalyst (B) is at least one kind selected from the group consisting of dimethylimidazole and benzylmethylimidazole; wherein, among the thiol compounds (A), the di- or higher-functional thiol compound having one or more sulfide bonds is at least one kind selected from the group consisting of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 4,8 or 4,7 or 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, bis(mercaptoethyl) sulfide, 2,5-bis(mercaptomethyl)-1,4-dithiane, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 4,6-bis(mercaptomethylthio)-1,3-dithiane, and 2-(2,2-bis(mercaptomethylthio)ethyl)-1,3-dithiethane; wherein, among the thiol compounds (A), the di- or higher-functional thiol compound having one or more ester bonds is at least one kind selected from the group consisting of pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), and thiol compounds represented by following General Formula : wherein, in the General Formula , 1 and m independently represent integers of 1 or 2, r represents an integer of 1 to 3, n represents 1 or 2, R represents hydrogen or a methyl group, and, in a case in which multiple R's are present, R's may be identical to or different from each other. a step of mixing di- or higher-functional thiol compounds (A) having one or more sulfide bonds and/or one or more ester bonds with an imidazole-based curing catalyst (B) to prepare a mixed solution; a step of mixing the mixed solution with an isocyanate compound (C) including at least one kind of a di- or higher-functional alicyclic isocyanate compound (c1) and/or a di- or higher-functional aliphatic isocyanate compound (c2) to prepare a polymerizable composition for optical materials; a step of injecting the polymerizable composition for optical materials into a mold; and a step of polymerization-curing the polymerizable composition for optical materials in the mold; wherein the imidazole-based curing catalyst (B) is at least one kind selected from the group consisting of dimethylimidazole and benzylmethylimidazole; wherein, among the thiol compounds (A), the di- or higher-functional thiol compound having one or more sulfide bonds is at least one kind selected from the group consisting of 4-mercaptomethyl-1,8-dimercapto-3,6-dithiaoctane, 4,8 or 4,7 or 5,7-dimercaptomethyl-1,11-dimercapto-3,6,9-trithiaundecane, bis(mercaptoethyl) sulfide, 2,5-bis(mercaptomethyl)-1,4-dithiane, 1,1,3,3-tetrakis(mercaptomethylthio)propane, 4,6-bis(mercaptomethylthio)-1,3-dithiane, and 2-(2,2-bis(mercaptomethylthio)ethyl)-1,3-dithiethane; wherein, among the thiol compounds (A), the di- or higher-functional thiol compound having one or more ester bonds is at least one kind selected from the group consisting of pentaerythritol tetrakis(2-mercaptoacetate), pentaerythritol tetrakis(3-mercaptopropionate), and thiol compounds represented by following General Formula : wherein, in the General Formula , 1 and m independently represent integers of 1 or 2, r represents an integer of 1 to 3, n represents 1 or 2, R represents hydrogen or a methyl group, and, in a case in which multiple R's are present, R's may be identical to or different from each other. <EOS>