AIR BAG DEVICE

PURPOSE:To adjust the internal pressure of a bag into the optimum state according to the deceleration/acceleration of a vehicle while simplifying structure. CONSTITUTION:An exhaust port 7 is provided, as the opening of a valve seat 6, at the casing 2 of the base part of a bag body 4, separately from the exhaust port 15 of the bag body 4, and a valve body 11 provided with a conical weight part 9 is inserted into this exhaust port 7. In the valve body 11, its shaft 10 is inserted into the claw hole 13 of the casing 2, and notches 12 are provided around the shaft 10. The inertial force of the weight part 9 of the valve body 11 becomes larger as deceleration/acceleration becomes larger so as to increase the number of notches 12 relatively surmounted by the claw hole 13 and thereby to reduce the area of an opening part 14 between the exhaust port 7 and the weight part 9. The generated gas flowing outside from the bag body 4 is thereby throttled to maintain the internal pressure of the bag body 4 even higher, and a driver is provided with bag body reaction corresponding to the deceleration/ acceleration.