A vehicle braking system including an input piston and a pressure piston that are moveably supported within a cylinder. The input piston is allowed to depress the pressure piston and is connected to the a brake pedal. Pressure chambers to the front and to the rear of the input piston are communicated through a communication passage such that the control hydraulic pressure in accordance with the operation amount to the brake pedal is applied to the second pressure chamber via first and second linear valves. The control hydraulic pressure in accordance with the operation amount to the brake pedal that has been transmitted to the pressure piston through the input piston is regulated by a pressure regulating valve so as to be applied to the second pressure chamber. The braking hydraulic pressure may be output from the pressure chambers, respectively.