The present invention is intended to provide a technology that can utilize the advantages of both a load sensing control and a regeneration circuit without causing any problem.A regeneration circuit is added to a hydraulic circuit provided with a hydraulic pressure signal line for detecting a hydraulic pressure value of a circuit and controlling a volume of hydraulic fluid to a cylinder 1 with reference to the detected value. A pressure reducing valve 6 that outputs a reduced pressure as an operating signal to a pump 2, and subsequently the controlling means 5 causes the pressure reducing valve 6 to output a pressure reduction command to a pump 2 and thus to reduce a discharge rate from the pump 2, when the regeneration circuit is in a regeneration state.