Vehicle braking system

A vehicle braking system comprising:

• a master cylinder for producing an upstream hydraulic pressure in response to an operation given to a brake operation part;
• an operation amount detector for detecting an operation amount of the brake operation part;
• a shut-off valve provided between the master cylinder and a wheel cylinder;
• a hydraulic-pressure source for producing a downstream hydraulic pressure between the shut-off valve and the wheel cylinder in a close instruction receiving condition of the shut-off valve;
• and
• a controller for setting a control target value in response to the downstream hydraulic pressure based on the operation amount and controlling the downstream hydraulic pressure based on the control target value, wherein
• the controller comprises:
• an upstream-hydraulic-pressure detector-estimator for detecting or estimating the upstream hydraulic pressure;
• and
• a regulator for adjusting the control target value in response to the operation amount or the upstream hydraulic pressure to regulate a pressure difference between the upstream hydraulic pressure and the downstream hydraulic pressure,
• wherein the upstream hydraulic pressure moves a valve element of the shut-off valve to open, and
• wherein if a value obtained by subtracting the control target value from the operation amount or the upstream hydraulic pressure is greater than a regulation value in a closed condition of the shut-off valve, the regulation value is adjusted by the controller.