A hydraulic brake apparatus for a vehicle includes a hydraulic pressure generator which generates and outputs a power pressure irrespective of brake pedal operation, a regulation valve which regulates the power pressure to a predetermined pressure corresponding to the brake pedal operation force and outputs the predetermined pressure, and a master cylinder having a master cylinder pressure chamber and an auxiliary pressure chamber connectable to an output side of the regulation valve. The master cylinder is operated by auxiliary pressure in the auxiliary pressure chamber to generate a master cylinder pressure corresponding to the auxiliary pressure. A wheel brake cylinder is operated by the master cylinder pressure to apply braking force to a wheel. A pressure modulation device is disposed in a pressure passage connecting the output side of the regulation valve to the auxiliary pressure chamber to modulate the auxiliary pressure to a pressure less than the predetermined.