PROBLEM TO BE SOLVED: To accurately detect a signal light component included in light that is reflected and scattered and so on by an object under test.SOLUTION: A light detection device includes: a photocurrent converting unit 100 including first and second photocurrent conversion element parts each for converting incoming light into current and outputting it, and outputting a differential current between the current outputted by the first photocurrent conversion element part and the second photocurrent conversion element part as a detection current a current voltage converting unit 200 amplifying the detection current detected from the photocurrent converting unit, converting it into a voltage signal and outputting the voltage signal as a detection signal and a fixed light component estimating unit estimating a fixed light component based on an integral value in a predetermined frequency range of power spectrum of the output detection signal.COPYRIGHT: (C)2013,JPO&INPIT【課題】被検体によって反射、散乱等された光に含まれる信号光成分を精度良く検出する。【解決手段】光検出装置は、入力光を電流に夫々変換して出力する第1光電変換素子部及び第2光電変換素子部を含んでなり、第1光電変換素子部が出力する電流と第2光電変換素子部が出力する電流との差分電流を検出電流として出力する光電流変換部100と、この光電流変換部から出力された検出電流を増幅して電圧信号に変換し、この電圧信号を検出信号として出力する電流電圧変換部200と、この出力された検出信号のパワースペクトルの所定の周波数範囲における積分値に基づいて、定常光成分を推定する定常光成分推定部とを備える。【選択図】図1
