PURPOSE: To enable to adjust a height of a vehicle so as to be low upon running and to be high at works by pivotable attaching fore and aft car bodies to front and rear of a chassis frame and enabling them to be rotatably in up-and-down directions by elevating cylinders.

CONSTITUTION: Fore and aft car bodies 2, 3 are pivotable attached to front and rear of a chassis frame 1 by pins 4, 5 while elevating cylinders 6, 7 are interposed between upper ends of vertical portions of the fore and aft car bodies 2, 3 and the chassis frame 1. Basic end portions of the elevating cylinders 6, 7 are pivotably attached to a bracket 9, provided at both sides of a slewing mechanism 8 provided at upper central portion of the chassis frame 1 by pins 10, 11 while tip end portions thereof are pivotably attached to top portions of the fore and aft car bodies by pins 12, 13, thereby, the fore and aft car bodies 2, 3 are made pivotable. On the other hand, a slewing car body 20 is slewably equipped above the chassis frame 1 through the slewing mechanism 8. According to this method, the height of the slewing car body 20 may be adjusted by extending or contracting the elevating cylinders 6, 7 and thereby moving the chassis frame 1 upwardly or downwardly.