A vehicle brake system for braking a vehicle including a braking-mode switching mechanism configured to selectively effectuate, depending upon situations of the vehicle brake system, one of (A) a regulated-pressure-dependent braking mode in which is generated a regulated-pressure-dependent braking force having a magnitude that depends on a regulated pressure of a working fluid and (B) a braking mode depending on an operation force and the regulated pressure in which are generated both of an operation-force-dependent braking force having a magnitude that depends on the operation force by a driver and the regulated-pressure-dependent braking force.