PURPOSE: To reduce time and labor required for adjusting work by multiplying the valve control current command value by such a correction factor as to enlarge/reduce a reference speed pattern to perform the correction of a speed pattern.

CONSTITUTION: In relation to a reference pattern outputted from a speed control device 13, a pattern correcting means performs the correction of enlarging or reducing the shape of the reference speed pattern on the basis of the oil temperature and load pressure detection value from an oil temperature sensor 17 and a load pressure sensor 16. Such a current pattern as to realize the speed pattern based on this correction is formed to control a valve device 9, and thus a stable travel characteristic is secured regardless of the characteristic change of oil caused by the fluctuation of oil temperature and load pressure. This results in reducing time and labor required for adjusting work.