PURPOSE: To perform both antiskid and traction control without changing spools by providing switching means for switching communication/cut-off between the output path of a master cylinder and master cylinder communicating ports and cut-off/communication between pump communicating ports and the master cylinder communicating ports.

CONSTITUTION: At the time of traction control, a pump 32 sucks a brake fluid from a path 6 on the master cylinder 2 side and discharges to transmit it to the first port 13 of a flow valve 9 on the driving wheel side through a solenoid change-over valve 57. Pressure is thereby applied to a wheel cylinder 4 to perform traction control. In the case of antiskid control, normally-closed solenoid valves 24, 25 are opened, and the spools 19 of the flow valves 9, 10 move downward. Communication between the first ports 13 and first holes 41 is thereby cut off, whereas the wheel cylinders 4, 5 are communicated with a reservoir 28, and fourth ports 18 are opened. In this case, the solenoid change-over valve 57 is put in the demagnetized state, so that the delivery pressure of the pump 32 is not returned onto the master cylinder 2 side.