PROBLEM TO BE SOLVED: To solve such a problem that, when an operation dial is released, a neutral return mechanism of an input unit is returned, in some cases unintentionally, to a neutral position by spring force, the input unit being mounted on an operation unit of a bending section at a distal end of an insertion device.SOLUTION: The insertion device includes the input unit to be provided in the operation unit is disposed in the operation unit housing, with an input operation part separated from the neutral return mechanism. When a movement angle by an operation of an operator exceeds an engagement range corresponding to a preset bending angle of the bending section, the neutral return mechanism performs a return operation for returning to a neutral position of the operator where the bending section becomes linear by energizing force of the spring, however, when the movement angle of the operator is within the engagement range, retains the bending state of that time.COPYRIGHT: (C)2014,JPO&INPIT【課題】挿入装置の先端の湾曲部の操作部に搭載される入力ユニットの中立復帰機構は、操作ダイヤルを離すと、バネ力により中立位置へ戻され、場合により不本意な動作となる。【解決手段】挿入装置は、操作部に設ける入力ユニットが入力操作部位と中立復帰機構と分離して操作部筐体内に配置される。中立復帰機構は、操作子の操作による移動角度が予め設定された湾曲部の湾曲角度に相対するエンゲージ範囲を越えた際に、バネの付勢力により湾曲部が直線状となる操作子の中立位置へ戻す復帰動作を行い、操作子の移動角度がエンゲージ範囲内であれば、その時の湾曲状態を維持する。【選択図】図1
