An air bag unit is provided to protect a vehicle passenger from impacting a member of the interior of a vehicle. The air bag unit includes one or more air bags attached as an integral unit to a clamping device for attachment to a portion of the interior vehicle frame. Since the air bag is intended to protect passengers from impact with an interior member of the vehicle frame, the air bag is adapted to the shape of such member. The clamping device includes an attachment part which slidably engages the interior of the vehicle frame. In addition, the air bag unit is inflated by a tube housed therein. The tube exerts a restraining action on the inflating gas and includes one or more breakage locations which are intended to rupture within the air bag at a predetermined pressure for inflation of the air bag.