PURPOSE: To reduce a force for operating a manual lever by driving one pump with hydraulic pressure of the other pump directly connected to the manual lever to lift rapidly a juck in non-load and lift the juck in high load only with the one pump.

CONSTITUTION: Oil in an oil tank 3 is pumped up into a pump 11 through a check valve 12 and forced into the lower end of a piston P1 of a pump 13 from a path at the side (a) of a change-over valve V1 by operating a manual lever L to compress a spring 14 and push up the piston P1. The ascend of the piston P1 pumps up oil from the tank 3 into the pump 13. Rapid suction and discharge of oil by the vertical movement of the large-sized piston P1 during the operation of the manual lever L are carried out by check valves 15, 16 to lift rapidly a ram 17 in non-load. Also, in high load on the ram 17, the change-over valve V1 is changed over to the side (b) to shut off a circuit to the pump 13 while oil is forcibly sent directly to the ram 17 from the pump 11 to lift the jack.