To reduce liquid leakage from a spool sliding clearance part of a spool valve in a device wherein a load liquid pressure is controlled by conducting switching between liquid introduction to a load from a liquid pressure source and liquid discharge from the load to a reserver by means of a spool valve capable of controlling a spool position.

Between a liquid pressure source including an accumulator 9 and a spool valve 20 a pressure control valve 30 is provided. By means of the pressure control valve 30, the liquid pressure in a pressure control chamber 34 is controlled so as to be constantly larger than the pressure of a wheel cylinder 6 (load pressure) by a predetermined value, and the controlled liquid pressure is introduced to an input port 23 of the spool valve 20.