without extending the measurement time, measure the living tissue while maintaining the SN ratio to provide an optical measuring device that can be. Optical measuring device 3, in the time until the end of measurement from the measurement start by the optical measuring device 3, a and the measuring light emission and stop together to execute alternately in the measurement light source unit 321, the measurement light to the measurement light source unit 321 an illumination control section 332a to emit the measuring light in the measurement light source unit 321 is longer emission time for emitting the measuring light than the stop time for stopping the detection of the measurement light of the return light by the first detecting unit 325 detects Of the strength, it includes a computing unit 332b for performing an operation to remove the detected intensity of the observation light of the return light by the endoscope, which is reflected in living tissue S1 a,測定時間を伸ばすことなく、SN比を維持した状態で生体組織を測定することができる光学測定装置を提供する。光学測定装置3は、光学測定装置3による測定開始から測定終了までの時間内において、測定用光源部321に測定光の出射と停止とを交互に実行させるとともに、測定用光源部321に測定光を停止させる停止時間よりも測定光を出射させる出射時間を長くして測定用光源部321に測定光を出射させる照明制御部332aと、第1検出部325が検出した測定光の戻り光の検出強度のうち、生体組織S1で反射した内視鏡による観察光の戻り光の検出強度を除去する演算を行う演算部332bと、を備える。
