Hydraulic brake device with improved braking sensitivity

The device has a master cylinder (13) with a hydraulic piston (95) defining a pressure chamber (7) connected to brakes arranged at levels of wheels. A hydraulic servomotor (11) has a hydraulic piston (15) dividing a chamber (5) into front and rear chambers (51, 53). The front and rear chambers are filled with braking hydraulic fluid at same pressure, where the fluid is provided by a hydraulic fluid source under high pressure. An independent claim is also included for a braking system.