In the endoscope apparatus, a side observation image is not lost so that a side shift image K is displaced between the optical axis of the imaging optical system and the center position L of the light receiving surface of the imaging unit. The image is shifted until the boundary between the image and the non-imaging region reaches the end of the light receiving surface, and the magnification of the imaging optical system is adjusted to enlarge and display the combined image of the front observation image and the side observation image.内視鏡装置は、撮像光学系の光軸と、撮像部の受光面の中心位置Ｌとの間にシフト距離Ｋの位置ずれが生じるように、側方観察像が欠如せずに側方観察像と非結像領域との境が受光面端に掛かるまでシフトされて、撮像光学系の倍率を調整して、前方観察像と側方観察像の合成画像を拡大表示する。
