A brake ECU brings master cut valves into an open state and brings holding valves into a closed state, thereby controlling a master cylinder and wheel cylinders to communicate to each other when a magnitude of a hydraulic pressure detected by an accumulator pressure sensor has decreased to a value less than a predetermined value set in advance. On the other hand, the ECU maintains holding valves in an open state, and controls an accumulator and the wheel cylinders to communicate to each other via linear control valves. Then, the ECU determines in which brake system a failure occurs out of a brake system for a front right wheel, a brake system for a front left wheel, and brake systems for rear right and left wheels based on changes in hydraulic pressure detected by a sensor, a master cylinder pressure sensor, and a control pressure sensor.