To control the regenerating flow rate according to the magnitude of counter load by controlling the opening of a regenerating passage according to pilot pressure and guiding the flow rate upstream from a fixed throttle to the regenerating passage.

When pilot pressure is guided to a pilot chamber 22 in a state where counter load acts on a second cylinder port 2, a regenerating spool S is moved against spring force, and a communication hole 26 is closed. When the communication hole 26 is closed, only the flow rate to be discharged to a tank passage 21 pass a fixed throttle 20. Accordingly, pressure equivalent to pressure loss by the fixed throttle 20 is produced on a return relay port 18. When the pressure becomes higher than pressure of a first cylinder port 1, a check valve 30 is opened, and return oil not discharged from the fixed throttle 20, of return oil allowed to flow to the return relay port 18 is regenerated to the first cylinder port 1. This regenerating flow rate is determined on the basis of the opening of an annular groove 25, namely, pressure of the pilot chamber 22.