In order to minimize spreading, without additional parts, of connecting bolts of a pneumatic brake booster in a manner which is brought about by the deformation of a bearing surface on a booster housing before and during its assembly on a provided vehicle body part, it is proposed that the bearing surface is assigned a planar surface section in an immediately adjacent manner which is configured so as to be plane-parallel with respect to the bearing surface and so as to be axially inwardly recessed on the booster housing with a circumferential step.