Airbag apparatus for automobile

An airbag apparatus for an automobile includes an airbag case (44) for accommodating an airbag (43) in a folded condition, the airbag case (44) being disposed behind a surface panel (40) which is made of a thermoplastic resin material and provided within the automobile; a fracture-opening section (46) of the surface panel (40), the fracture-opening section (46) facing an opening of the airbag case (44) and being defined by means of fracture grooves (40b,c) formed on an inside surface of the surface panel (40); at least one reinforcement plate member (47) fixed to the inside surface of the surface panel (40) in a region corresponding to the fracture-opening section (46); and a frame member (45) surrounding the reinforcement plate member (47) and fixed to the inside surface of the surface panel (40) in a region surrounding the fracture-opening section (46). The frame member (45) and the reinforcement plate member (47) are each made of a thermoplastic resin material, and are fixed to the inside surface of the surface panel (40) through vibration welding.