An electric parking brake system includes a wheel driven by an electric motor to move a vehicle, a parking brake maintaining the wheel stopped, a parking brake actuator operating the parking brake, and a drive controller controlling the parking brake actuator. The drive controller controls the electric motor to maintain the wheel of the vehicle stopped while the vehicle is parked, and calculates a parking torque based on a control amount of the electric motor that maintains the wheel stopped. The drive controller calculates a necessary braking force for the parking brake to maintain the wheel stopped based on the calculated parking torque, and controls the parking brake actuator so that the necessary braking force is generated.