PURPOSE: To prevent slipping out of a bearing further increase rigidity of a corner angular part, by securing reinforcing plates to an internal surface part in the vicinity of an outside flange part.

CONSTITUTION: Reinforcing plates 15 are secured to an internal surface part in the vicinity of an outside flange part 3 in a front axle housing 2 and constituted such that this plate 15 can be adapted to the side of an outer ring 14b of a bearing 14 for axially supporting a front wheel driving axle 1, accordingly the ring 14b of the bearing 14 receiving the lateral thrust load acting upon the axle 1 by mesh driving of an upper located bevel gear mechanism is suppressively stopped by the plate 15. Further the flange part 3 and outside part of the housing 2 are reinforced by said plates 15, and rigidity of a corner angular part of said flange part 3 is remarkably increased.