In an apparatus for reducing noises in a space, signals related to noise generating conditions of a plurality of noise sources are detected, a signal component of the detected signals is selected on the basis of determination of which signal component is predominant over the other signal component in the noises in the space, and the selected signal component is filtered through adaptively determined filter coefficients to output drive signals to control sound source, the filter coefficients being updated through a control algorithm so as to reduce a residual noise of a residual noise detector such as microphones. The signal components to be selected include a signal component having a relatively high auto-correlated function characteristic and a signal component having a random characteristic.