PURPOSE: To inexpensively and more accurately control a cage speed by controlling a motor by a pattern signal considering the variation of leak in a pump even to the variation above mentioned.

CONSTITUTION: An inverter 23 is controlled corresponding to a cage load signal 6a, cage speed signal 8a, oil temperature signal 16a, and operation signal 30da in a speed control device 25. A bias pattern correcting the leak quantity in a hydraulic pump 12 is previously added to a travel pattern corresponding to a cage speed command, also the difference with an actual cage speed is corrected by detecting a speed and position respectively at the time of the rising and lowering operation of a cage 5 by the excitation of an electromagnetic directional control valve 11 to always return to the addition pattern above mentioned, and a pattern signal for motor drive, corresponding to the variation of the leak quantity in the hydraulic pump 12, is produced. A motor 13 is variable-speed controlled by open control by the pattern signal, and the travel of the cage 5 is controlled by driving the hydraulic pump 12 and conforming the actual cage speed to a suitable travel pattern.