To separate tube ends welded on ends of axle cases of an axle housing in favorable working efficiency.

In the axle housing H which includes tubular axle cases H21, H22 extending to right and left from a body H1 accommodating a differential gear and which welds to fix tubular tube ends T1, T2 on end openings of the respective axle cases H21, H22, a load is applied on the tube end T1 in a direction cross to its axle while the axle case H21 is positionally fixed so as to destroy the welding part between the axle case H21 and the tube end T1 after the welding bead between the axle case H21 and the tube end T1 is removed. Subsequently, the tube end T1 is extracted.