A valve system of a braking device provided with a stroke simulator that is connected via a connection passage with a pipe for making a master cylinder communicate with a wheel cylinder; and a third shut-off valve that is a solenoid valve and performs opening and closing of a communication between the master cylinder and the stroke simulator, wherein the third shut-off valve is a normally closed valve; and the valve system opens the third shut-off valve by applying a start-up voltage, thereafter keeps the open state of the third shut-off valve by alternately applying a holding voltage that is lower than the start-up voltage and the start-up voltage, in order to prevent heat generated in the valve from becoming excessively high even while keeping the open state of the valve.