An active control system is provided with an actuator which controls a noise and/or vibration state of an automotive vehicle, a detector which detects the noise and/or vibration state of the vehicle, and a control unit which receives an output signal of the noise and/or vibration state detector and outputs a signal to control the actuator, the control unit having a neural net which compares a control predicted value based on the output signal with a control target value so that a correction for connection weights in the neural net is carried out on the basis of the comparison result.