In a bearing unit for a drive shaft mounted cantilevered in a housing by means of two rolling bearings and having a driving bevel gear wherein the drive shaft is mounted in the drive housing via a bearing bush and the bearing bush is axially supported at one end by a bearing bush support part and the rolling bearings are supported in the bearing bush spaced from the one end thereof so that, during heating, the bearing bush expands inwardly toward the driving bevel gear mounted on the shaft whereas the drive housing expands outwardly away from the driving bevel gear, the gear drive housing and the bearing bush consist of a light metal alloy and the bearing bush support part consists of an iron material.