A brake system and a brake device for use with automobiles is provided in which braking energy stored in an auxiliary pressure source can be effectively used for braking, even if an electrical system fails. The vehicle brake system includes a proportional pressure control valve for generating braking liquid pressure by adjusting the braking energy stored in the auxiliary pressure source. A passage transmits the liquid pressure generated by a brake pedal stroke, a switching valve opens the passage in the powered condition and closes the passage in the off-powered condition, and an auxiliary control portion activates the proportional pressure control valve. Even in the off-powered condition, the high pressure accumulated in the auxiliary pressure source can be used to adjust the required braking liquid pressure at the proportional pressure control valve.