PURPOSE: To prevent such an accident during lifting of a rear body that it falls down by touching the control lever by mistake by providing a valve controlling lever and an hydraulic control valve for handling in the cab.

CONSTITUTION: In a cab 2 of a truck so designed that the rear body can be lifted up and down by the expansive and contracting action of an hydraulic cylinder 4 interposed between rear body and a car-body, a control lever 5, which is to change over the hydraulic cylinder 4 into expansion contraction, or stop position in interlocked motion with a control valve V, is mounted on a bracket 6 in parallel with a control lever 8 of the power take-up device 7. A flexible cable 9 is used for the purpose of connecting this control lever 8 with the power take-up device 7. According to this constitution, the operating sytem of the control lever 5 is not exposed to the working site, so that such an accident that the rear body falls down during lifting by touching the control lever by mistake, can be prevented.