To reduce blur of captured images by increasing an irradiation light quantity to a part to be observed when capturing still images.
A beam splitter 32 is provided in an optical path connecting a light source 26 and a scope 11. The beam splitter 32 splits a luminous flux B1 from the light source 26 into transmission light and reflected light. A light quantity control system is provided in order to control the irradiation light quantity to the scope 11. When capturing still images, a light source device is set to be a high irradiation mode, and the beam splitter 32 is withdrawn from the optical path. At the time, since the luminous flux B1 does not pass through the beam splitter 32, the light quantity is increased, exposure time becomes short, and the blur of images is suppressed.
Hiroki Ogura
Shigeru Torayama
Takuya Fuji