Abstract: Disclosed is a brake device constructed to supply a pressure fluid from a pressure source to brake actuating devices of the wheels of a vehicle. The brake device includes a brake retainer valve which has a valve element arranged in a valve chamber and a valve seat on which the valve element is seated and unseated. In the brake device, when on an upward slope the brake pedal and the clutch pedal are depressed. Sequentially, the pressure fluid is not released from the brake actuating devices to the pressure source by seating the valve element on the valve seat in spite of returning the brake pedal, and the pressure fluid is released by removal of the valve element from the valve seat by returning the clutch pedal. In the brake retainer valve, a solenoid is provided, which is connected to the device for detecting the backward driving of the vehicle to prevent seating of the valve element on the valve seat by attracting the valve element away from the valve seat.