An endoscopic surgical operation apparatus and a mantle tube which can easily obtain an image desired by a surgeon and have high operability are provided. The mantle tube is provided with a slider inside the mantle tube main body for guiding the endoscope and the treatment instrument in the body cavity. A dead zone region in which the endoscope coupling portion and the treatment instrument coupling portion are provided inside the slider and the other does not interlock with the advance and retreat movement of either one of the endoscope and the treatment tool, And a sensitive zone region in which the other moves in conjunction with one of the forward and backward movements. In the mantle tube main body, the treatment instrument is configured to be rotatable around the axis without changing the positional relationship between the endoscope and the treatment instrument with respect to the mantle tube main body.術者が望む画像を簡単に得られ、操作性の高い内視鏡下外科手術装置及び外套管を提供する。外套管は、体腔内に内視鏡及び処置具を案内する外套管本体の内部にスライダを備える。スライダの内部には内視鏡連結部及び処置具連結部が設けられ、内視鏡及び処置具のいずれか一方の進退移動に対して他方が連動しない不感帯領域と、内視鏡及び処置具のいずれか一方の進退移動に対して他方が連動する感帯領域とを有する。外套管本体は、外套管本体に対する内視鏡及び処置具の位置関係を変えることなく、処置具を軸周りに回転可能に構成する。
