Patent ID: 8360466

Claim:
A side airbag apparatus comprising an airbag that includes a thorax protecting portion for protecting the thorax of an occupant seated in a vehicle seat, wherein, the airbag is formed by stacking a pair of fabric portions in a widthwise direction of the vehicle seat and joining the fabric portions to form a bag-like shape, wherein the airbag is arranged beside the occupant in a folded state, and is inflated and deployed in a forward direction of the vehicle seat from the folded state, the thorax protecting portion includes: a gas supply port that supplies the inflation gas to the thorax protecting portion, thereby inflating the thorax protecting portion; and a thickness limiting portion that is formed by connecting the fabric portions to each other after bringing the fabric portions into one of a state in which the fabric portions contact with each other and a state in which the fabric portions are close to each other, at a position that is forward of the gas supply port and that corresponds to an arm of the occupant, wherein the thickness limiting portion limits the thickness of the thorax protecting portion in the widthwise direction of the vehicle seat, to prevent the thorax protecting portion from pushing the arm toward the thorax, and the thickness limiting portion has an arcuate portion that is curved to bulge toward a rear portion of the airbag, the thorax protecting portion is folded back along a folding line to be partitioned into a main protecting portion, to which the inflation gas is supplied from the gas supply port, and an auxiliary protecting portion, to which the inflation gas is supplied via the main protecting portion, wherein, before the airbag is folded, the folding line is located above the gas supply port and extends through the thickness limiting portion, and the rear end of the arcuate portion of the thickness limiting portion is located in the auxiliary protecting portion.