PURPOSE: To enhance safety, by obtaining an image to be observed by succeedingly taking an image on the basis of a timing signal by a solid-state image sensing element when the rotation of a rotary color filter is stopped to display the signal of the taken image on a monitor.

CONSTITUTION: When the rotation of a rotary color filter 16 is stopped by the trouble of a motor 15, the stop position of the rotary color filter 16 becomes the position, when a green transmitting filter 18G is interposed on a light path, by a wt. part 22 and, in this state, the illumination light of a lamp 14 transmits through the green filter to be projected on the incident end of a light guide 9. That is, an object is irradiated with green illumination light. Therefore, even in such a state that the rotary color filter 16 is stopped, the image of the object can be taken and, by looking the image on a monitor 6, the operation drawing an electronic scope 2 out of the body can be safely performed and the operation drawing a treatment device out of the body can be also performed. Further, since an image to be observed can be obtained, treatment using the treatment device can be succeedingly performed.