In an electric power steering system, a low-pass filter (61) executes a low-pass filtering process on a detected steering torque value (T) detected by a torque sensor (11). A steering torque deviation computing unit (62) computes a deviation ”T between a detected steering torque value T* obtained through the low-pass filtering process and the detected steering torque value (T) detected by the torque sensor (11). A PI control unit (63) generates a vibration compensation value (Ic) used to lead the detected steering torque value (T) to the steering torque value (T*) obtained through the low-pass filtering process, by executing PI computation on the steering torque deviation (”T) computed by the steering torque deviation computing unit (62).