To provide a pulse oximeter which can improve measurement accuracy and can simplify an operation circuit.SOLUTION: A pulse oximeter has: an LED 103 that simultaneously emits red light and near infrared light； a first photodetector 104 for receiving transmitted light of light of a light emitting unit, which has been transmitted through a measurement site, and detecting red light contained in the transmitted light； a second photodetector 105 for receiving the transmitted light of the light of the light emitting unit, which has been transmitted through the measurement site, and detecting near infrared light contained in the transmitted light； and a signal processing unit 203 that obtains SpObased on detection results of the first and second photodetectors 104, 105.SELECTED DRAWING: Figure 2【課題】測定精度を向上し得、かつ、動作回路を簡単化し得るパルスオキシメータを提供すること。【解決手段】パルスオキシメータは、赤色光及び近赤外光を同時に発光するＬＥＤ１０３と、測定部位を透過した発光部の光の透過光を受光し、当該透過光に含まれる赤色光を検出する第１のフォトディテクター１０４と、測定部位を透過した発光部の光の透過光を受光し、当該透過光に含まれる近赤外光を検出する第２のフォトディテクター１０５と、第１及び第２のフォトディテクター１０４、１０５の検出結果に基づいてＳｐＯ２を得る信号処理部２０３と、有する。【選択図】図２
