Air bag module with vent

The gas generator (12) is joined to a carrying base (10). A lateral opening (14) facilitates a pressure reduction inside the airbag if required. The opening (14) is covered by a flap (16, 20) made of plastic all of a piece including the linear joining area (18, 22). A locking mechanism in the shape of two hooks integrated in the rear of the flap (16, 20) keeps the flap in an open position in a particular situation as in the case of second impact. The flap (16, 20) is provided with reinforcing ribs located at the rear surface.