In an electric power steering system, a low-pass filter executes a low-pass filtering process on a detected steering torque value detected by a torque sensor. A steering torque deviation computing unit computes a deviation ΔT between a detected steering torque value T* obtained through the low-pass filtering process and the detected steering torque value detected by the torque sensor. A PI control unit generates a vibration compensation value used to lead the detected steering torque value to the steering torque value obtained through the low-pass filtering process, by executing PI computation on the steering torque deviation computed by the steering torque deviation computing unit.