The measuring apparatus (10) comprises a casing (100), a translucent member (102), a light emitting means (120), a first light detecting means (140), a second light detecting means (142), and a light guiding member ). An opening (101) is provided in the housing (100). The translucent member (102) is located in the opening (101) and transmits at least the light of the first wavelength. The light emitting means (120) is disposed inside the housing (100) and outputs light including light of a first wavelength. The first light detection means (140) and the second light detection means (142) are disposed inside the housing (100) and detect light of the first wavelength. The light guide member (160) is provided between the light emitting means (120) and the second light detecting means (142). The optical axis of the first light detecting means (140) and the optical axis of the light emitting means (120) pass through the opening (101) and intersect with each other outside the casing (100).測定装置(10)は、筐体(100)、透光部材(102)、発光手段(120)、第1光検出手段(140)、第2光検出手段(142)、および導光部材(160)を備える。筐体(100)には開口(101)が設けられている。透光部材(102)は、開口(101)内に位置し、少なくとも第1波長の光を透過する。発光手段(120)は、筐体(100)の内部に配置され、第1波長の光を含む光を出力する。第1光検出手段(140)および第2光検出手段(142)は、筐体(100)の内部に配置され、第1波長の光を検出する。導光部材(160)は、発光手段(120)と第2光検出手段(142)との間に設けられている。そして、第1光検出手段(140)の光軸および発光手段(120)の光軸は、開口(101)を通り、筐体(100)の外で互いに交わる。
