PURPOSE: To rationally execute without problems of danger of explosion, public pollution by adhering a skin material to a base material of an interior material of an automobile with crosslinked polyolefin film.

CONSTITUTION: Ethylene-vinyl acetate copolymer is extruded by a T-die to obtain a film having 0.1mm. The film is irradiated with a curtainlike electron beam in dose of 5Mrad at 150keV by using a low energy electron beam accelerator to obtain a crosslinked film having a gel fraction of 30%. This film is adhered to a PP foam side of a laminated sheet with PP foam of PVC of a skin material by using a hot roll at 130°C. The sheet is so heated that its surface temperature becomes 150°C, vacuum molded to a door base material made of a previously molded wood board, held in vacuum evacuation for 30sec, and cooled.