To facilitate the shift of a ridge which is straddled by two front wheels 4 and two rear wheels 3 to the next one while turning by 180° at the end of the ridge in a moving agricultural working machine supported by the wheels 3, 4 and driven by operation with a controlling handle 5 extending backwards.

Both the front wheels 4 are vertically moved under interlocking with both the rear wheels 3 by an elevation cylinder 10 to move the moving machine body 1 vertically. On the other hand, the elevation arm 16 supporting both the front wheels 4 is widely jumped up by a hydraulic cylinder 21 for jumping, and this enables two-wheel running by both the rear wheels. Further, an operation lever 25 for jumping is attached on the controlling handle 5, so that the operability is improved.