PURPOSE: To accurately prevent the malfunction of an air bag device with a simple constitution, at the time it is connected to or disconnected from a vehicle, by providing a prohibiting means by which a switch means is prohibited from becoming a closed condition until the detection signal of a signal generating means is received.
CONSTITUTION: In an air bag device 1, it is detected through a grounding terminal 80a whether or not the air bag device 1 has been fitted to a steering wheel 60. In this case, the electrification to a squib 2 that has been formed in an inflator is prohibited by a collision judging circuit 107 until the air bag device 1 is brought into the condition that it is fitted to a steering wheel 60 from the condition that it is not fitted, so that the, erroneous explosion is not caused. Since the start of the air bag device 1 or the electrification to the squib 2 is prohibited for a prescribed time after the air bag device 1 has been fitted, the,erroneous explosion of the inflator due to the shock when it is mounted or fitted can be surely prevented.
IMAI KOJI
OTAKA KOJI
