PURPOSE: To immediately recover hydraulic pressure so as to enhance reliability of braking by nullifying hydraulic control signals so as to return solenoid valves to a normal braking condition when detecting the abnormality of a microcomputer, and also performing control such that a pump for returning a brake fluid from a reservoir to a master cylinder is actuated.

CONSTITUTION: If some abnormality occurs in a microcomputer 22 and actuating signals of fixed waveform are not output therefrom any more, an abnormality detection circuit 23 detects this abnormality and outputs control signals to a solenoid relay drive circuit 26 and an one-shot multivibrator circuit 24. Thereby a solenoid relay 33 is turned off and solenoids 34 are all turned off and hydraulic control signals are nullified so that solenoid valves 13,16 are both returned to a normal braking condition after hydraulic control is inhibited. Also control signals are output to a motor drive circuit 25 for a fixed time and a relay switch 32 is on to operate the motor 19 of a pump 18 so that a brake fluid is returned from a reservoir 17 to a master cylinder 12 for a fixed time thereby recovering hydraulic pressure which has been reduced.