The present invention intends to provide an air bag door construction in which the air bag develops smoothly and securely, the skin can be easily produced with small man-hour, and which is excellent in the surface appearance. The skin 50 is formed by a mold 5 including an endless and annular wall 50 provided at a part of a molding surface to be inclined relative to the molding surface. A groove portion 35 of the skin 3 formed by the wall 50 is cut at a bottom portion thereof to separate the skin 3 into a general portion 30 and a door portion 31. The general portion 30 and the door portion 31 are relatively shifted to make both surfaces thereof flush with each other. When the surfaces of the general portion 30 and the door portion 31 are flush by the relative shift, gap between the general portion 30 and the door portion 31 can be narrowed, and gap appeared on the surface can also be narrowed. Also, when the skin is disposed in the mold for foam forming, the skin can position the general portion 30 and the door portion 31 in the desired position easily, and will not scatter a skin chip in the development of the air bag.