A vehicle brake apparatus includes a brake pedal, a wheel brake cylinder operatively mounted on a wheel for applying a braking force to the wheel in proportion to a hydraulic braking pressure, a pressure source for pressurizing brake fluid to generate a hydraulic braking pressure and supply the hydraulic braking pressure to the wheel brake cylinder, and an auxiliary pressure source for pressurizing brake fluid in response to operation of the brake pedal to generate a hydraulic braking pressure and supply the hydraulic braking pressure to the wheel brake cylinder when the pressure source is non-operational. A mechanical valve is operatively mounted between the wheel brake cylinder and the auxiliary pressure source. A first passage is connected between the auxiliary pressure source and the mechanical valve and a second passage is connected between the mechanical valve and the wheel brake cylinder. The mechanical valve permits brake fluid communication between the first and the second passages when the pressure in the first passage is less than a predetermined pressure, and permits brake fluid to flow from the first passage to the second passage when the pressure of the first passage is more than the predetermined pressure.