An audio signal processing method includes: obtaining an L signal including a sound localized closer to the left as a major component and an R signal including a sound localized closer to the right as a major component; extracting a first signal which is a component of a sound included in the L signal and localized closer to the right and a second signal which is a component of a sound included in the R signal and localized closer to the left; generating a first output signal by subtracting the first signal from the L signal and adding the second signal to the L signal and a second output signal by subtracting the second signal from the R signal and adding the first signal to the R signal; and outputting the first output signal and the second output signal.