The measuring apparatus (10) includes a housing (100), an opening (102) provided in a part of the housing (100), a light source disposed in the housing (100) and irradiating light including the first wavelength A first light detecting unit (140) disposed in the housing (100) toward the opening (102) and detecting the light of the first wavelength a light emitting unit (120) A reflecting member (130) arranged at a position that does not overlap with the optical axis L of the light emitting unit (120) but overlaps with the light emitting area A of the light emitting unit (120) And a second light detection unit (142) which is disposed toward a position overlapping the radiation area of the first wavelength and detects the light of the first wavelength.測定装置(10)は、筐体(100)と、筐体(100)の一部に設けられた開口(102)と、筐体(100)の内部に配置され、第1波長を含む光を開口(102)に向けて放射する発光部(120)と、筐体(100)の内部に開口(102)に向けて配置され、第1波長の光を検出する第1光検出部(140)と、発光部(120)の光軸Lに重ならず、発光部(120)の光の放射領域Aと重なる位置に配置された反射部材(130)と、筐体(110)の内部に光の放射領域と重なる位置に向けて配置され、第1波長の光を検出する第2光検出部(142)と、を備える。
