The present invention aims to provide a photocurable resin composition which rapidly cures by irradiation with active energy rays such as ultraviolet rays and is excellent in adhesion to an electrolyte membrane which is a hard-to-bond material. A photocurable resin composition includes the following ingredients (A) to (C): ingredient (A): a polymer having one or more (meth)acryloyl groups and having a polyisobutylene skeleton containing a —[CH2C(CH3)2]— unit, ingredient (B): a photoradical polymerization initiator, and ingredient (C): a compound having a (meth)acryloyl group and a cationic polymerizable functional group in one molecule.