To provide a net airbag to protect an occupant from the shock at the time of collision since there is no airbag at the rear seat of a vehicle of these days.

A sensing sensor 8 is mounted at the front side and rear side of the vehicle, an explosive is actuated by energizing at the time of collision, and the net airbag is pulled down as a reaction to protect the head. Since the bag is made of net, there is little shock to be safe.