Even with existing endoscopes, in order to accurately detect the rotational direction regardless of the posture of the endoscope, the endoscope system (1) is captured at the distal end of an elongated insertion section (5) optical an endoscope comprising a system (6), the patients body surface (a), attached through said body table the (a), the trocar having a through hole for passing the insertion part (5) (2) ( and 3), provided in the trocar (3), the rotation sensor for detecting the amount of rotation of the longitudinal axis of the insertion portion disposed in the through state to the through-hole (2) (5) and (4), the trocar (3 ) is disposed in a position that can be photographed by the photographing optical system of the endoscope (6) when inserted into the display and capable of identifying the circumferential position of the through hole (2), obtained by the photographing optical system image based on the display in the insertion portion (5) and the through hole initial angle detection that detects a relative angle upon insertion of (2) And a (7).既存の内視鏡を用いても、内視鏡の姿勢に関係なく精度よく回転方向を検出することを目的として、内視鏡システム(1)は、細長い挿入部(5)の先端に撮影光学系を備える内視鏡(6)と、患者の体表(A)に、該体表(A)を貫通して取り付けられ、挿入部(5)を貫通させる貫通孔(2)を有するトロッカ(3)と、該トロッカ(3)に設けられ、貫通孔(2)に貫通状態に配置された挿入部(5)の長手軸回りの回転量を検出する回転センサ(4)と、トロッカ(3)に挿入される際に内視鏡(6)の撮影光学系により撮影され得る位置に配置され、貫通孔(2)の周方向位置を特定し得る表示と、撮影光学系により取得された画像中の表示に基づいて、挿入部(5)と貫通孔(2)との挿入時の相対角度を検出する初期角度検出部(7)とを備える。
