PURPOSE: To simplify constitution by forming the first selector valve for cutting off the part between a master cylinder side and a wheel brake side when an ASR operates and the second selector valve for the communication between a wheel brake device side and the fluid pressure source for a fluid pressure booster, into unit form.

CONSTITUTION: The solenoid valve 40 of an ASR is equipped with the first selector valve 41 arranged midway in a brake pipe 22 on the rear wheel side as drive wheel and the second selector valve 42 arranged midway in a passage for the communication between the wheel brake device 24a and 24b side of the selector valve 41 and the hydraulic source of a hydraulic booster 50 (fluid pressure booster). Though an ABS is brake-controlled to prevent the drive slip on brake application, the ASR is brake-controlled for preventing the drive slip on start, and the simultaneous operation of the both control is prevented, and in the hydraulic control unit 30 of the ABS, a three-position three-directional electromagnetic selector valve 35 is used for the both. The valves 41 and 42 parts or the selector valve 40 is formed into unit, which are installed onto the body of a hydraulic booster 50.