PROBLEM TO BE SOLVED: To provide an endoscope which has a sufficiently narrow diameter and enables inside the body to be observed over a wide range from the front to the side, resulting in improvement in work efficiency of a surgery, and which has a simple optical system thereby being disposable.SOLUTION: An endoscope 1 with a built-in optical system includes a long-length body 11 to be inserted into a body cavity, and an imaging part 12 disposed at an end on the distal end side of the long-length body 11. The imaging part 12 includes: an imaging device 125 with an imaging surface 124 arranged along the longitudinal direction of the endoscope 1 an optical lens 127 whose light incident surface 126 is disposed obliquely to the longitudinal direction of the endoscope 1, and which forms images of observation ranges A-D on the imaging surface 124 and a diaphragm member 128 provided on the light incident surface 126 of the optical lens 127 and provided with a hole part 131 formed to causes light to be incident on the imaging surface 124.COPYRIGHT: (C)2013,JPO&INPIT【課題】十分に径が細く、かつ前方から側方まで広範囲に渡って体内を観察できることで手術の作業性向上につながり、また簡便な光学系を有することで使い捨て可能である内視鏡を提供する。【解決手段】光学系を内蔵した内視鏡1であって、体腔内に挿入される長尺体11と、前記長尺体11の先端側の端部に配置された撮像部12と、を有し、前記撮像部12は、前記内視鏡1の長手方向に沿って撮像面124が配置された撮像素子125と、前記内視鏡1の長手方向に対して光の入射する面126が斜めに配置されて、前記撮像面124に観察範囲A~Dの画像を結像する光学レンズ127と、前記光学レンズ127の光の入射する面126に設けられ、前記撮像面124に光が入射する穴部131が形成された絞り部材128と、を有する内視鏡1である。【選択図】図2
