To hasten the change in operating speed of a hydraulic actuator in relation to the amount of operation of a lever to improve the responsiveness, and slowly change the operating speed of the hydraulic actuator to reduce the burden on an operator during the fine operation of the lever, in a pilot operated circuit for construction machines.

Change-over valves 11, 12 are provided respectively in pilot oil paths 5, 6 between right and left pilot ports 2, 3 of a hydraulic pilot type directional control valve 1 and a pilot valve 4. With the change-over valves 11, 12, throttling positions 11c, 12c are provided in the middles of spools, and open positions 11a, 11b and 12a, 12b are provided respectively on both ends of the spools. Then, the pressures of the pilot oil paths 5, 6 are introduced into both ends of the spools of the respective change-over valves, pilot springs 15a, 15b and 16a, 16b are provided on both ends of the respective spools, and the change-over valves are switched from the throttling positions to the open- positions when the pressures in the oil paths exceed the pressures set by the springs.