PROBLEM TO BE SOLVED: To provide a biological light measurement device having high safety for eyes of a measurement subject (eye-safety) even if optical strength of a measurement light is enhanced.SOLUTION: The biological light measurement device includes: a return light measurement means 12 which receives and measures a return light Lb formed by reflection of a measurement light Lm on the terminus of a measurement light irradiation means 7 and propagating through the measurement light irradiation means 7 in a direction opposite to the propagation direction of the measurement light Lm and a measurement light control section 11b which, when a result of measurement of the return light Lb shows the determination that the terminus of the return light measurement means 7 is not in contact with a measured section 20, controls a measurement light emitting means 2 so as to lower the optical strength of the measurement light Lm or stops the emission of the measurement light Lm.COPYRIGHT: (C)2012,JPO&INPIT【課題】測定光の光強度を強くしても、被測定者の目に対する安全性(アイセーフティ)が高い生体光測定装置を提供を提供する。【解決手段】測定光Lmが測定光照射手段7の終端で反射して、測定光照射手段7を測定光Lmの伝播方向と反対方向に伝播する戻り光Lbを受信し計測する戻り光計測手段12と、戻り光計測手段12で戻り光Lbを計測した結果、測定光照射手段7の終端が被測定部20に接触していないと判断されるとき、測定光Lmの光強度を低くするように測定光射出手段2を制御するか、あるいは測定光Lmの射出を停止する測定光制御部11bと、を備えたものである。【選択図】図1
