Disclosed is an audio signal processing method including: receiving a stereo signal; transforming the stereo signal into a frequency-domain signal; rendering the first signal based on a first ipsilateral filter coefficient; generating a frontal ipsilateral signal relating to the frequency-domain signal; rendering the second signal based on a second ipsilateral filter coefficient; generating a side ipsilateral signal relating to the frequency-domain signal; rendering the second signal based on a contralateral filter coefficient; generating a side contralateral signal relating to the frequency-domain signal; transforming an ipsilateral signal, generated by mixing the frontal ipsilateral signal and the side ipsilateral signal, and the side contralateral signal into a time-domain ipsilateral signal and a time-domain contralateral signal, which are time-domain signals, respectively; and generating a binaural signal by mixing the time-domain ipsilateral signal and the time-domain contralateral signal.