The power spectrum calculation section that time-frequency converter for converting a frequency signal to an acoustic signal of breathing of the living body and (2) to calculate the power spectrum of each frequency of the frequency signal (3), the power spectrum calculation section (3) Based on the similarity of the similarity calculating section for calculating the power spectrum of the current calculated by the similarity of the power spectrum in the past (4), the calculated similarity calculating unit (4), is included in the acoustic signal with judges judging breathing unit, (6) and respiratory status of a living being, it is detected without being affected by the state of sleep and individual differences respiratory state of a living body.生体の呼吸時の音響信号を周波数信号に変換する時間・周波数変換部(2)と、周波数信号の周波数毎のパワースペクトルを算出するパワースペクトル算出部(3)と、パワースペクトル算出部(3)により算出された現在のパワースペクトルと、過去のパワースペクトルとの類似性を算出する類似性算出部(4)と、類似性算出部(4)により算出された類似性に基づき、音響信号に含まれる生体の呼吸状態を判定する呼吸判定部(6)と、を備え、生体の呼吸状態を個人差や睡眠の状態に影響を受けずに検出する。
