Automatic brake control unit

The automatic brake control unit can be applied to an automatic braking device including a reservoir that can suck a brake fluid discharged from a master cylinder, and a cut valve that can permit or prohibit the introduction of the brake fluid into the reservoir. The unit opens the cut valve during automatic brake control. Thus, the brake fluid discharged from the master cylinder according to a brake-pedal stroke is sucked into the reservoir by the maximum capacity of the reservoir during a brake override. Consequently, the relationship between the brake-pedal stroke and the wheel-cylinder pressure during the brake override can be brought close to that for the case where automatic brake control is not in operation.