To provide a method for producing a gas barrier film capable of providing a gas barrier film improved in a gas barrier property, and improved in productivity.

According to this invention, a method for producing a gas barrier film including at least one gas barrier layer on a base material includes a coating film formation process of applying a solution containing a polysilazane compound to the surface of the base material to form a coating film, and a reforming treatment process of subjecting the coating film to reforming treatment by directly irradiating the coating film with vacuum-ultraviolet light, wherein 10 sec or more of an irradiation pause period from pause of the direct irradiation of the vacuum-ultraviolet light to the coating film to restart of the vacuum-ultraviolet light irradiation is set at least once during the reforming treatment process.