A main body apparatus includes a first detection fiber that transmits light received by an endoscope a first beam splitter that divides the light transmitted by the first detection fiber into a first optical path and a second optical path, and can guide the light a second detection fiber that is a detection fiber different from the first detection fiber, and that transmits light received by the endoscope a second beam splitter that reflects the light transmitted by the second detection fiber into a third optical path oriented in the same direction as the first optical path, and can guide the light a photodetector that can detect light intensities of the light from the first optical path and the third optical path and an auxiliary image pickup device that can receive the light from the second optical path.
