In an electric parking brake system, the moving force-based target tension is set based on the inclination angle of a vehicle and the shift position, and the slack compensation amount is determined based on the inclination angle of the vehicle and the shift position. The control target tension is set to a smaller value from among the slack-based target tension, which is the sum of the moving force-based target tension and the slack compensation amount, and the maximum value of the output power that can be produced by an electric motor. The electric motor is controlled such that the tension of the cable matches the control target tension (the slack-based target tension, in most cases).