If the pump for antilock fluid pressure control is used as a fluid pressure source for automatic brake control, the pressure rising speed will drop, deteriorating the responsiveness of the device, or otherwise an extremely large pump-driving motor has to be used. To solve this problem, a fluid supply amplifier and a pressure-responsive valve are provided parallel to each other between a pump and a wheel brake fluid pressure control valve. A solenoid valve is closed until the output fluid pressure rises to a predetermined value to amplify the amount of fluid discharged from the pump with the fluid supply amplifier. It is thus possible to increase pressure sufficiently quickly. At the same time, it is possible to increase the output of the pump-driving motor. When the output fluid pressure exceeds the predetermined value, the pressure-responsive valve opens, so that brake fluid is now supplied directly from the pump into the wheel brake. The brake pressure can thus be increased to a high level.