A physiological SpO2Which can detect a noise section of a pulse wave signal without erroneously determining a fluctuation of a pulse wave signal as a noise section, and a control method therefor.SOLUTION: A predetermined section is cut out from first and second pulse wave signals detected using light of the first and second wavelengths. An evaluation value indicating the relationship between the measured value group of the first pulse wave signal and the measured value group of the second pulse wave signal with respect to the predetermined section is calculated based on the logarithm value of the measurement value group, And judges the presence or absence of noise in the section.(FIG.【課題】生理的なSpO2の変動をノイズ区間と誤判定することなしに、脈波信号のノイズ区間を検出可能な生体信号解析装置およびその制御方法を提供すること。【解決手段】第1および第2の波長の光を用いて検出された第1および第2の脈波信号から所定の区間を切り出す。そして、所定の区間についての、第1の脈波信号の計測値群と第2の脈波信号の計測値群との関係を示す評価値を、計測値群の対数値に基づいて、所定の区間におけるノイズの混入有無を判定する。【選択図】図3
