A hydraulic brake apparatus for a vehicle is provided. The hydraulic brake apparatus includes a master cylinder, a high hydraulic pressure source, a brake assist mechanism, a liquid reservoir, an electronic control device, a hydraulic control device and is configured such that the master cylinder is actuated by a force assisted by the brake assist mechanism to generate a hydraulic pressure and a braking force according to the hydraulic pressure is applied to a wheel of the vehicle. The hydraulic brake apparatus further includes driving pressure reducing valve which is configured such that when a hydraulic pressure in a master pressure input port is higher than that in the driving pressure input port by a predetermined value, the hydraulic brake apparatus is actuated based on the pressure difference to open a hydraulic pressure discharge path extending from a driving hydraulic pressure chamber to the liquid reservoir.