the invention relates to a gas bag module comprising a gas bag , an outer contour of the gas bag being defined by a gas bag wall which has a front wall for the impact of an occupant and a depression starting from the front wall . the depression is formed in that during inflation of the gas bag a center portion of the gas bag wall is prevented from freely moving and is restrained . the gas bag has around the depression a ring - shaped chamber to be filled with gas . at least one limiting strap is provided which engages the gas bag wall at a transition from the front wall to the depression , substantially extends alongside the depression and determines a depth of the depression .