A sine wave signal generated in synchronism with a pulse signal determining a frequency of vibrations and noises generated by a vibration/noise source is input to a W filter and a C filter. The C filter selects filter coefficients dependent on the rotational speed of an engine, and generates a transfer characteristic-dependent reference signal R dependent on a transfer characteristic of a vibration/noise-transmitting path, based on the filter coefficients. Alternatively, a divisional signal is prepared by dividing a repetition period of vibrations and noises by a predetermined number, and values of a sine wave generated in synchronism with occurrence of said divisional signal is delivered to a W filter, while the transfer characteristic-dependent reference signal is delivered from the C filter storing data of the transfer characteristic identified in advance to the W filter. Alternatively, a sine wave signal and a delayed sine wave signal delayed by a quarter of a repetition period of the sine wave relative to the sine wave, as well as phase and amplitude-related information of the transfer characteristic of the path are generated and delivered in synchronism with generation of the divisional signal. These sine wave signals and the transfer characteristic-dependent reference signal (phase and amplitude-related information) are used to actively control the vibrations and noises.