An acoustic processing device comprises: a resonant band detecting means that detects a resonant band of sound output from a speaker based on a measurement result of a predetermined measurement signal reproduced through the speaker; an analyzing means that analyzes the measurement result of the predetermined measurement signal; a control parameter generating means that generates a control parameter for controlling the resonant band detected by the resonant band detecting means based on an analysis result by the analyzing means; and an audio signal controlling means that controls an audio signal input from a predetermined audio signal reproducing device based on the control parameter generated by the control parameter generating means such that a resonant band component of reproduced sound of the audio signal is suppressed to be short on a time axis.