An operation handle (2) operated by a user in a body cavity, a treatment section (3) for holding a predetermined surgical instrument which is inserted into the body cavity and operated by the operation section so as to be replaceable, and the operation. A connecting part (4) is provided between the handle part and the treatment part for arranging the surgical instrument held by the treatment part at a desired position in a body cavity in a desired posture, and the connection part is , At least two or more connecting parts (7a) that are connected in series in the major axis direction of the connecting part and constitute joints (7, 8) that enable rotation about the major axis or about an axis orthogonal to the major axis. , 7b, 8a, 8b) and the two or more connecting portions are moved toward or away from each other to open the angle about the major axis of the joint and/or the angle about the axis orthogonal to the major axis. Alternatively, it has a connecting portion control mechanism that restrains the treatment portion and thereby arranges the treatment portion at a desired position and posture in the body cavity. [Selection diagram]【解決課題】 体腔内でユーザが操作する操作ハンドル(2)部と、体腔内に挿入され前記操作部によって操作される所定の手術器具を換装可能に保持する処置部(3)と、前記操作ハンドル部と前記処置部との間に設けられ前記処置部が保持する手術器具を体腔内の所望の位置に所望の姿勢で配置するための連結部(4)とを有し、前記連結部は、該連結部の長軸方向に直列的に接続され、長軸回り若しくは長軸と直交する軸回りの回動を可能にする関節(7,8)を構成する少なくとも２以上の接続部(7a,7b,8a,8b)と、前記２以上の接続部を互いに近接若しくは離間する方向に移動させることで、前記関節の長軸回りの角度若しくは／及び長軸と直交する軸回りの角度を開放若しくは拘束し、それにより前記処置部を体腔内の所望の位置及び姿勢で配置する連結部制御機構とを有するものである。【選択図】 図１
