An apparatus estimates the direction of a sound source from signals plural microphones capture sound to produce. Data are stored on reverse characteristics of spatial transfer functions defined on sound transmitted from sound source positions to the respective microphones. To the signal produced by each microphone, applied are the reverse characteristics of the spatial transfer functions thus stored in connection with that microphone with respect to the sound source positions to thereby estimate a sound source signal on a sound source position associated with the sound captured. Between the sound source signals estimated on the sound source positions associated with the sounds captured by the microphones, coincidence or higher correlation is found on a sound source position to thereby produce information on at least the direction of the sound source thus found.