An electric parking brake system includes motors, parking brakes, current a detection portion, a drive circuit, and a controller. The parking brakes are driven by the motors to apply braking force to wheels. The current detection portion detects the amount of current supplied to the motors. The drive circuit supplies a constant predetermined voltage to the motors. The controller controls supply of electricity to the motors. The drive circuit is controlled by the controller. When a detected current value exceeds a predetermined value, the controller stop supplying electricity to the motors.