A detection device (1, 1a, 30, 101, 300) comprising: a detector (2, 110, 110S) detecting sound waves generated by a bodily motion; an acquiring unit (11, 131, 131A, 131B) acquiring burst information on at least one of the duration and frequency of a burst during which a cluster of pulses appears in a waveform of the sound waves detected by the detector (2, 110, 110S); a memory (20, 180) storing reference information on reference values compared with the burst information, the reference values differing from each other depending on the types of bodily motions generating sound waves; and a determining unit (12, 132, 132A, 132B) comparing the burst information with the reference information to determine which of bodily motions has caused the sound waves detected by the detector (2, 110, 110S), characterized in that: the sound waves are inaudible to a human; and that the detector (2, 110, 110S) detects ultrasound having a frequency not less than 20 kHz and not more than 70 kHz, as the sound waves, and outputs an ultrasonic signal in accordance with the detected ultrasound; the detection device further comprising an audible converter (5, 122) for converting the ultrasonic signal to a low frequency audio signal, and an A/D converter (7,123) for converting the low frequency audio signal to a digital detection signal and for outputting the digital detection signal to the acquiring unit (11, 131, 131A, 131B), wherein the acquiring unit (11, 131, 131A, 131B) acquires the burst information based on the digital detection signal. a detector (2, 110, 110S) detecting sound waves generated by a bodily motion; an acquiring unit (11, 131, 131A, 131B) acquiring burst information on at least one of the duration and frequency of a burst during which a cluster of pulses appears in a waveform of the sound waves detected by the detector (2, 110, 110S); a memory (20, 180) storing reference information on reference values compared with the burst information, the reference values differing from each other depending on the types of bodily motions generating sound waves; and a determining unit (12, 132, 132A, 132B) comparing the burst information with the reference information to determine which of bodily motions has caused the sound waves detected by the detector (2, 110, 110S), characterized in that: the sound waves are inaudible to a human; and that the detector (2, 110, 110S) detects ultrasound having a frequency not less than 20 kHz and not more than 70 kHz, as the sound waves, and outputs an ultrasonic signal in accordance with the detected ultrasound; the detection device further comprising an audible converter (5, 122) for converting the ultrasonic signal to a low frequency audio signal, and an A/D converter (7,123) for converting the low frequency audio signal to a digital detection signal and for outputting the digital detection signal to the acquiring unit (11, 131, 131A, 131B), wherein the acquiring unit (11, 131, 131A, 131B) acquires the burst information based on the digital detection signal. the sound waves are inaudible to a human; and that the detector (2, 110, 110S) detects ultrasound having a frequency not less than 20 kHz and not more than 70 kHz, as the sound waves, and outputs an ultrasonic signal in accordance with the detected ultrasound; the detection device further comprising an audible converter (5, 122) for converting the ultrasonic signal to a low frequency audio signal, and an A/D converter (7,123) for converting the low frequency audio signal to a digital detection signal and for outputting the digital detection signal to the acquiring unit (11, 131, 131A, 131B), an audible converter (5, 122) for converting the ultrasonic signal to a low frequency audio signal, and an A/D converter (7,123) for converting the low frequency audio signal to a digital detection signal and for outputting the digital detection signal to the acquiring unit (11, 131, 131A, 131B), wherein the acquiring unit (11, 131, 131A, 131B) acquires the burst information based on the digital detection signal.