Abstract: A head-protecting air bag apparatus includes an air bag which is adapted to be fixed to a vehicle body so that the air bag extends from a pillar along a roof side rail and one of a front end and a rear end of which is fixed to an inflator. The air bag includes, at an intermediate portion thereof, a plurality of first noninflatable portions which intersect a tension line connecting the front and rear ends when the air bag is expanded, extend in a substantially vertical direction, and are located at a roof side region corresponding to the roof side rail. The air bag also includes a guide portion. The guide portion has a portion corresponding to the pillar and an extended portion extending to a first noninflatable portion of the plurality of first noninflatable portions which is adjacent to the one end.

Abstract: An air bag (11) for a side air bag device capable of reducing the size and weight of the device (M1) while retaining a tension line (L--L) when expanded is mounted on the peripheral edge of a door opening (W) at the inside of a compartment, and is formed into a generally rectangular bag shape for covering the door opening when expanded, while being equipped with a gas inlet (19) for introducing an expanding gas. The air bag is provided with joints (22) jointing an inner side wall (12) and an outer side wall (13) partially so as to form a tension line L--L when expanded. The individual joints (22) are juxtaposed in plurality along the tension line so as to cross the tension line, and are arranged generally at vertically middle portions so as to form one expansion chamber (18) having upper and lower spaces (18a and 18b) for the expanding gas to flow therethrough.