PURPOSE: To provide a means capable of supplying the exact flow rate necessary to operate a fluid apparatus by combining skillfully a flow route change-over valve and a flow rate control valve to make a supply volume of pressure fluid as little as possible when no load is applied, and increasing gradually the controlled flow rate with increase of the load.

CONSTITUTION: By skillfully combining a flow route change-over valve 12 for operatively sensing a load applied to the side of a fluid apparatus and joining the pressure fluid flowing from a plurarity of pumps 1, 2 and a flow rate control valve 21 for sensing alteration of the load applied to the fluid apparatus and changing a back flow rate of a part of pressure fluid flowing through a supply route to be fed back to the side of a tank 3, the supply volume of pressure fluid can be made minimum when no load is applied and the controlled flow rate can be gradually increased with increase of the load so as to enable the flow rate to be sufficient and necessary for operating the fluid apparatus. Accordingly, the supply volume of pressure fluid can be controlled rationally or effectively, and power consumption is decreased to the lowest to save energy.