A coating agent has: a film-forming component containing an organosilicon compound having a radical polymerizable functional group and an alkoxysilyl group; and a film-curing component composed so that a base and a radical can be generated on irradiation with ultraviolet light. The film-curing component includes a nonionic photobase generator having no ionic bond in the molecular structure. The content of the nonionic photobase generator is 0.1 parts by mass or more and 50 parts by mass or less, based on 100 parts by mass of the organosilicon compound.

A coating agent has: a film-forming component containing an organosilicon compound having a radical polymerizable functional group and an alkoxysilyl group; and a film-curing component composed so that a base and a radical can be generated on irradiation with ultraviolet light. The film-curing component includes a nonionic photobase generator having no ionic bond in the molecular structure. The content of the nonionic photobase generator is 0.1 parts by mass or more and 50 parts by mass or less, based on 100 parts by mass of the organosilicon compound.