PURPOSE: To stabilize a pressure level by cutting off an intermediate passage from an outlet port by a first valve spool when a control port is prescribed pressure, and communicating an inlet port with the intermediate passage by a second valve spool when in high prescribed pressure.

CONSTITUTION: When fluid pressure of a supply pipeline 14 becomes a first pressure level, a valve spool 29 moves rightward by a piston 53 so that an intermediate passage 24 is cut off from an outlet port 23. When the fluid pressure becomes a high second pressure level, a valve spool 32 moves rightward so that the supply pipeline 14 is communicated with the outlet port 23. When fluid pressure of a control port 22 becomes the first pressure level by actuating a steering circuit 16, a spring device 36 moves the valve spool 29 leftward, and the intermediate passage 24 is communicated with the outlet port 23 so that pressure of the intermediate passage 24 suddenly reduces. A spring device 43 suddenly moves the valve spool 32 leftward, and an inlet port 21 is cut off from the intermediate passage 24 so that fluid is supplied to the steering circuit 16. Cut-in and cut-out pressure levels can be accurately set by adjusting a preload of the spring device.