Method for forming a laminated film on a substrate

A method for forming a film on a substrate by continuous vapor deposition includes: introducing the substrate into a film-forming apparatus; conveying the substrate into a pretreatment compartment of a pressure reduction chamber of the film-forming apparatus; performing plasma pretreatment of the substrate including supplying a plasma source gas composed of argon and at least one of oxygen, nitrogen, carbon dioxide gas and ethylene, introducing the plasma source gas that has been supplied as plasma into a gap between a magnet of the pretreatment compartment and a pretreatment roller such that the plasma is entrapped in the gap, and holding the plasma and applying a voltage between the pretreatment roller and a plasma-supply nozzle; conveying the substrate into a vapor deposition compartment of the pressure reduction chamber; and forming the film by vapor deposition on a surface of the substrate which has been pretreated.