An compact imaging apparatus having an OCT function is provided. An image formed of the illuminating-light reflected from a examination area is displayed on a monitor. A signal-light for obtaining an optical tomographic image is guided in a fiber through an insertion portion and projected onto a living tissue measurement area by an illuminating lens. The measurement area is scanned with the signal-light by a Piezo actuator moving the output face of the fiber. An OCT obtaining-portion obtains and displays on a monitor an optical tomographic image by using the interference caused by the signal-light reflected from the measurement area and a reference-light. By performing the scanning with the signal-light using an image-obtaining lens, the need to insert a probe for obtaining an optical tomographic image through a forceps port is eliminated. Therefore, the number of required forceps ports is reduced, and the insertion portion can be made thin.