A support unit for a shoulder belt of a safety belt system provided with a rolling mechanism in the form of an integrated component of a seat structure of an airplane seat. A sectional traverse girder is mounted approximately on shoulder level between the side walls of the seat structure of an airplane seat. The transverse girder has a guide slot for the shoulder belt and at least two support webs for the rolling mechanism are clamped in a frictionally engaging manner into the transverse girder.