To provide the manufacturing method of an air bag storing body with surface layer (surface part) easy to tear along an assumed break line along with a core layer simultaneously at the emergency time when the air bag is inflated and developed and favorable appearance, provided with the surface layer which can prevent the invasion of a dust.

This manufacturing method of an air bag storing body comprises thermally-softening a multi-layered body having a core layer 2 with at least a prescribed thickness and a surface layer 3 laminated on one surface side of the core layer 2, molding by pressing to the recessed surface 70 of a molding die consisting of a projected die 8 and recessed die 7, and forming the surface layer 3 to the outer periphery side contacting to the recessed die surface 70. The storing body has the recessed part for storing the air bag on the inner periphery side. At the molding time of the multi-layered body, a hole 3c is formed by penetrating the surface layer 3 by the boring member moving from the core layer 2 side to the surface layer 3 side, thereafter, the opening 30 of the hole 3c is closed by thermally fusing the surface contacting to the at least recessed surface 70 of the surface layer 3.