An audio signal processing method executed by an audio signal processing device includes: calculating a time difference between: when a sound emitted from a sound source arrives, as a direct sound, from a sound source position to a listening position; and when the sound is reflected by a reflector to become a reflected sound and arrives at the listening position; obtaining the time difference calculated and an audio signal indicating the reflected sound; determining whether to select the reflected sound, based on: the time difference obtained; a characteristic of an object involved in sound propagation; a first sound volume corresponding to a direction from the sound source position to the listening position; and a second sound volume corresponding to a direction from the sound source position to a reflector position; and outputting an output signal based on the audio signal indicating the reflected sound determined to be selected.