REFLECTED LIGHT MEASURING APPARATUS

PROBLEM TO BE SOLVED: To provide a reflected light measuring apparatus capable of efficiently measuring irradiation light and reflected light by one optical fiber even in a narrow place.SOLUTION: A fluorometer, which is a reflected light measuring apparatus for applying irradiation light to a measuring object and measuring reflected light from the measuring object, includes: a propagating optical fiber for propagating the irradiation light applied to the measuring object and the reflected light from the measuring object due to irradiation of the irradiation light; and a light separation circuit arranged on an optical path of the irradiation light or the reflected light to separate the irradiation light or the reflected light. The propagating optical fiber is a double-core photonic band gap fiber or a double-core photonic crystal fiber for guiding input light from the light separation circuit into the measuring object on a center core part and propagating the reflected light from the measuring object through a large-diameter core of the same axis as the center core part.