Based The near-infrared spectroscopy, a plurality of irradiation in order to separate the light absorption changes in the surface layer and the deep layer of the living tissue - in a biological optical measurement device using a probe having a detector distance (SD distance), by adjusting the amount of attenuation of the light transmitting or receiving light, to stabilize the light-receiving sensitivity in each subject, each site. And light, emitted from the light source to the irradiation point on the object, a detector for detecting the light propagated within the object, the light source-between subjects or photodetectors - the subject It has a light attenuation amount adjusting means which is disposed on the optical path, and the analysis unit for analyzing the signals, and a display unit for displaying the analysis results, each of the light source and the detector, the irradiation point and the detection point SD distance defined as the distance between are arranged such that two or more, the analysis unit analyzes the measured signals, and calculates the light attenuation adjustment amount for each of the received light amount within a predetermined range the optical attenuation amount adjusting means, from the analysis results, the attenuation of light by changing the amount of light incident on the detector, and each adjustable.近赤外分光法に基づき、生体組織の表層および深層における光吸収変化を分離するために複数の照射-検出器間距離(SD距離)を有するプローブを用いた生体光計測装置において、送光または受光する光の減衰量を調整することで、受光感度を各被検者・各部位で安定化する。 光源と、光源から被検体上の照射点に照射され、被検体内を伝播した光を検出するための検出器と、光源~被検者または光検出器~被検者間の光路上に設置される光減衰量調整手段と、信号を解析するための解析部と、解析結果を表示するための表示部とを有し、光源と検出器の各々は、照射点と検出点間の距離として定義されるSD距離が2種以上となるように配置され、解析部は、計測信号を解析し、各々の受光量を所定の範囲内とするための光減衰調整量を算出し、光減衰量調整手段は、解析結果から、光の減衰量を、検出器に入射する光量を変化させることにより、各々調整可能とする。
