Abstract: A device for inflating a gas bag comprising an end member or socket member which is airtightly disposed at one end of a gas bomb, and a gas generating device which is detachably disposed in the end member or socket member. The end member or socket member includes a seal plate which hermetically isolates the interior of the end member or socket member and the interior of the gas bomb and which is broken upon actuation of the gas generating device. In filling the gas bomb with a high pressure gas for the initial inflation of the gas bag, the gas generating device is detached from the end member or socket member, so that the filling job can be safely carried out.