A brake system for a vehicle including a master cylinder in which a front pressure chamber and a rear pressure chamber are defined by movably supporting an input piston and a pressure piston in a cylinder. A high-pressure supply pipe of an accumulator is coupled to wheel cylinders via hydraulic supply pipes, and coupled to the rear pressure chamber via a hydraulic supply pipe and a second hydraulic pipe. Pressure booster valves and pressure reducing valves are attached to the hydraulic pressure supply pipes, respectively. The wheel cylinder is coupled to the front pressure chamber via the first hydraulic pipe, and a coupling pipe for coupling a first hydraulic pipe and the hydraulic supply pipe is provided with the switching valve.