Vehicle brake device comprises a master cylinder including a master chamber connected to a wheel cylinder, a drive pressure chamber in which a drive pressure is generated for driving a master piston and a fluid pressure chamber in which a fluid pressure is generated in response to a stroke position of the master piston and an operating characteristics setting device for setting operating characteristics of an electromagnetic valve. The operating characteristics include a relationship of the pressure differential in the fluid conduit between the master cylinder side and the wheel cylinder side with respect to the electromagnetic valve based on the supply amount of the electric power detected by the supplied electric power detecting device.