Vibrations of a hydraulic pressure in an upstream portion due to operations of a slip control device during anti-lock control are transmitted to a control pressure chamber via a pressurizing piston of a master cylinder and a control piston of a regulator. During anti-lock control, in contrast, a pressure-increase linear valve and a pressure-reduction linear valve are opened, allowing change in volume of the control pressure chamber, resulting in reduction in stiffness. This reduction suppresses vibrations of a hydraulic pressure in the control pressure chamber, resulting in suppression of vibrations of a hydraulic pressure in a front pressure chamber. As a result, it is possible to reduce the lowering in control accuracy for a hydraulic pressure in a brake cylinder in anti-lock control using the hydraulic pressure in the front pressure chamber, which can well avoid a long braking distance.