A photocuring method comprising a step 1 and a step 2 performed after the step 1; wherein in the step 1, in the presence of compound having a carbonyl group generating a radical by photoirradiation and a carboxyl group decarboxylated by photoirradiation, silane coupling agent having a mercapto group or a (meth)acryl group is reacted with water under acidic conditions to obtain silane compound having a mercapto group or a (meth)acryl group and at least one silanol group, and in the step 2, in the presence of the compound and compound having a carbonyl group generating a radical by photoirradiation and a group generating a base by being decarboxylated by photoirradiation, the compound and the compound are irradiated with light to create alkaline conditions in a reaction system by decarboxylating the carboxyl group of the compound and generating a base from the compound, and radicals are generated from the compound and the compound to generate a crosslinked product containing a constitutional unit derived from the silane compound from the silane compound and, if necessary, from compound having two or more polymerizable unsaturated groups; wherein the compound is a compound represented by a general formula; wherein R 1 to R 8 each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 14 carbon atoms, an arylalkyl group having 7 to 15 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a halogen atom, a nitro group, a group represented by a general formula, or a group represented by a general formula, R 9 and R 10 each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 14 carbon atoms, an arylalkyl group having 7 to 15 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a halogen atom, or a nitro group; or represent a state where R 9 and R 10 are bonded to each other through an oxygen atom, a sulfur atom, or a carbonyl group, provided that at least one of the groups represented by R 1 to R 8 is the group represented by the general formula; wherein R 11 and R 12 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms; wherein Z 1 + represents an amidinium cation, a guanidium cation, a biguanidinium cation, or a phosphazenium cation, and R 13 and R 14 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms; wherein the compound is a compound represented by a general formula; wherein R 15 to R 22 each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 14 carbon atoms, an arylalkyl group having 7 to 15 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a halogen atom, a nitro group, a group represented by a general formula, or a group represented by a general formula, R 23 and R 24 each independently represent a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, an aryl group having 6 to 14 carbon atoms, an arylalkyl group having 7 to 15 carbon atoms, an alkoxy group having 1 to 12 carbon atoms, a halogen atom, or a nitro group; or represent a state where R 23 and R 24 are bonded to each other through an oxygen atom, a sulfur atom, or a carbonyl group, provided that at least one of the groups represented by R 15 to R 22 is the group represented by the general formula; wherein R 11 and R 12 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms; wherein Z 1 + represents an amidinium cation, a guanidium cation, a biguanidinium cation, or a phosphazenium cation, and R 13 and R 14 each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms.