Abnormal sound detection device

An abnormal sound detection device that detects abnormal sounds included in operating sounds of a target device that is a subject to be inspected, the abnormal sound detection device being provided with: a sound acquisition unit (10) that acquires the operating sounds of the target device as sound pressure time signals, which are time signals indicating time changes in the intensity of the sound pressure signals; a signal conversion unit (22) that converts the sound pressure time signal to a frequency characteristic indicating the intensity of the sound pressure signal for each frequency; an abnormal sound enhancement unit (23) that, on the basis of the frequency characteristics, finds an abnormal sound enhancement signal obtained by enhancing the intensity of a sound pressure signal at a frequency related to an abnormal sound of the target device among sound pressure signals at each frequency in the frequency characteristics; and an abnormal sound determination unit (25) that determines, on the basis of the