An object sound extraction apparatus includes sound source separation sections for separating and generating an object sound separation signal corresponding to an object sound and reference sound separation signals corresponding to the other reference sound based on each combination of a main acoustic signal and sub acoustic signals, an object sound separation signal synthesis section for synthesizing the object sound separation signals, and a spectrum subtraction processing section for extracting an acoustic signal corresponding to the object sound from the synthesis signal by performing a spectrum subtraction processing between the synthesis signal and the reference sound separation signals. Accordingly, in acoustic environments where the object sound and the noises are mixed in the acoustic signals obtained via the microphones, and the mixed conditions can vary, a high object sound extraction performance can be ensured by a small object sound extraction apparatus.