The endoscope operation mechanism 40 includes a dial 42 for operating an endoscope function, and a sensor rotation shaft 45a for detecting the rotation amount when the rotation of the dial rotation shaft 42a of the dial is transmitted, and the detected rotation amount. And a detection sensor 45 that outputs an electrical signal corresponding to the driving function of the driving source of the endoscope function to the dial rotating shaft 42a by applying a turning force in a direction opposite to the rotating direction to the dial 42. An initial position return mechanism 44 for returning the pivot position to the initial position, a first state in which the turning force from the initial position return mechanism is applied to the dial turning shaft 42a, and the turning force to the dial turning shaft 42a. And a switching mechanism 50 that is switchable between the second state and the second state.内視鏡操作機構４０は、内視鏡機能を操作するダイヤル４２と、ダイヤルのダイヤル回動軸４２ａの回動が伝達されて回動量を検出するセンサ回転軸４５ａを有し、検出した回動量に応じた電気信号を内視鏡機能の駆動源を駆動制御する制御部に出力する検出センサ４５と、回動された方向に反する方向の回動力をダイヤル回動軸４２ａに与えて、ダイヤル４２の回動位置を初期位置に復帰させる初期位置復帰機構４４と、ダイヤル回動軸４２ａに初期位置復帰機構からの回動力を与える第１の状態と、ダイヤル回動軸４２ａに前記回動力を与えない第２の状態と、に切り換え自在な切換機構５０と、を具備する。
