PROBLEM TO BE SOLVED: To provide a fluorescence detection device in which deterioration of detection accuracy due to autofluorescence of an optical waveguide is suppressed. A fluorescence detection device is composed of light sources 21A and 21B that emit excitation lights L1 and L2 that excite a fluorescent substance contained in a sample 110, and a material containing a fluorescent substance that is excited by the excitation light. The optical waveguide 4 that guides the fluorescence L3 generated in the sample irradiated with the excitation light, the fluorescence detection unit 24 that detects the intensity of the fluorescence that enters from the optical waveguide, and the intensity of the detected fluorescence. Has a control unit 30 for measuring the amount of the fluorescent substance of the sample based on the above, and a time measuring unit, and the control unit irradiates the optical waveguide with the excitation light regardless of the measurement of the amount of the fluorescent substance, and causes the autofluorescence of the optical waveguide. The extinction process for reducing the light intensity is repeated at predetermined time intervals. [Selection diagram] Figure 2【課題】光導波路の自家蛍光に起因する検出精度の低下を抑えた蛍光検出装置を提供する。【解決手段】蛍光検出装置は、試料１１０に含まれる蛍光物質を励起させる励起光Ｌ１，Ｌ２を出射する光源２１Ａ，２１Ｂと、励起光により励起される蛍光物質を含む材料で構成され、励起光を導波し、かつ励起光が照射された試料で生じた蛍光Ｌ３を導波する光導波路４と、光導波路から入射する蛍光の強度を検出する蛍光検出部２４と、検出された蛍光の強度に基づいて試料の蛍光物質量を測定する制御部３０と、計時部とを有し、制御部は、蛍光物質量の測定にかかわらず、励起光を光導波路に照射させて光導波路の自家蛍光を低減させる消光処理を所定の時間間隔で繰り返す。【選択図】図２
