A dual cushion air bag unit for cushioning contact between an occupant and interior side members of a vehicle during a side impact collision includes a lower bag portion and an upper bag portion which are joined by a relatively short and narrow neck portion in communication with both of said upper and lower bag portions and in which is located, in sealed relation, at least the outlet ports of a gas generator or inflator. Both of the lower and the upper bag protions are filled simultaneously by one inflator.