The external endoscope mechanism 10 includes a wheel 41 that engages with a second bending operation up/down knob 3g of a second bending operation device 3b provided in the operation portion 3 of the endoscope 1, and a drive that rotates the wheel 41. A motor 32 that generates a force, an operation switch 60 that outputs a drive control signal for the motor 32, a housing case 11 that houses the wheel 41 and the motor 32, and a housing case 11 that is detachably attached to the operation unit 3. A switch case 61 which is attached to the case attachment/detachment fixing part 12 and is attached to the housing case 11 and is rotatable between a first position which covers a part of the operation part 3 and a second position which is separated from the first position. And the operation switch includes an operator arranged in a housing portion provided in the rotating member, and the operation controller is operated on the front surface side of the rotating member to drive the drive control signal of the drive source. Is output.内視鏡用外付機構１０は、内視鏡１の操作部３に設けられた第２湾曲操作装置３ｂの第２湾曲操作上下ノブ３ｇに係合するホイール４１と、ホイール４１を回転させる駆動力を発生させるモータ３２と、このモータ３２の駆動制御信号を出力する操作スイッチ６０と、ホイール４１、モータ３２を収容する収容ケース１１と、収容ケース１１を操作部３に着脱自在に取り付けるためのケース着脱固定部１２と、収容ケース１１に取り付けられ、操作部３の一部を覆う第１の位置とこの第１の位置より離間した第２の位置との間で回動可能なスイッチケース６１と、を具備しており、操作スイッチは回動部材に設けられた収容部に配置される操作子を備え、回動部材の表面側で操作子が動作されることで駆動源の駆動制御信号を出力する。
