A laminate film manufacturing method is capable of preventing thickness unevenness of a cured layer and preventing wrinkling of the entire laminate film. A laminate film is manufactured by applying a coating solution including an active radiation curable resin to a surface of a first film that is continuously transported in an application part to form a coated film in a lamination part, laminating a second film that is continuously transported on the coated film to sandwich the coated film between the first film and the second film, and in a state in which the coated film is sandwiched between the first film and the second film, winding the first film around a backup roller and irradiating the coated film with infrared rays from an ultraviolet irradiation device while continuously transporting the first film to cure the coated film in a curing part so as to form a cured layer.