The object of the present invention is to provide a vehicle braking force generator capable of detecting a lock failure quickly. A vehicle braking force generator includes a motor cylinder device that generates a brake hydraulic pressure according to an operation amount of a brake pedal, a motor current obtaining unit that obtains a torque current according to an electric motor, a brake hydraulic pressure obtaining unit that obtains a brake hydraulic pressure generated in a cylinder unit, a movement amount obtaining unit that obtains a movement amount of pistons to a compression direction of a brake fluid relative to the cylinder unit, and a determination unit that determines an operation state of the motor cylinder device.