Provided are a mantle tube and an endoscopic surgical apparatus that can remove foreign substances adhering to an observation window of an endoscope by a simple operation and can always ensure a good field of view. A fluid supply / exhaust port 500 for sending cleaning water is provided at the distal end portion of the endoscope insertion passage 306 through which the endoscope insertion portion 102 of the outer tube 300 is inserted. When cleaning the observation window of the endoscope insertion portion 102 inserted through the endoscope insertion passage 306, the operator can remove the endoscope insertion portion 102 from the endoscope insertion passage 306 by using the positioning mechanism and remove the distal end surface. 114 can be set to a predetermined positioning position. As a result, a concave cleaning reservoir 502 communicating with the fluid supply / discharge port 500 on the distal end side from the distal end surface 114 of the endoscope insertion portion 102 is formed inside the distal end side of the endoscope insertion passage 306. In this state, the cleaning water is supplied from the fluid supply / discharge port 500, the cleaning water is stored in the cleaning storage unit 502, and the foreign matter in the observation window is removed. Subsequently, the cleaning water stored in the cleaning storage unit 502 is sucked from the fluid supply / discharge port 500 to remove water droplets from the observation window.簡便な操作によって、内視鏡の観察窓に付着した異物を取り除くことができ、常に良好な視界を確保することができる外套管及び内視鏡用外科手術装置を提供する。外套管３００の内視鏡挿入部１０２を挿通する内視鏡挿通路３０６の先端部に洗浄水を送出する流体給排口５００が設けられる。内視鏡挿通路３０６を挿通した内視鏡挿入部１０２の観察窓を洗浄する場合に、操作者は、内視鏡挿入部１０２を内視鏡挿通路３０６から抜き取ることなく位置決め機構により先端面１１４を事前に決められた位置決め位置に設定することができる。これによって、内視鏡挿通路３０６の先端側内部において内視鏡挿入部１０２の先端面１１４から先端側の流体給排口５００と連通する凹状の洗浄貯留部５０２が形成される。この状態において流体給排口５００から洗浄水を供給し、洗浄貯留部５０２に洗浄水を貯留するとともに観察窓の異物を除去する。続いて洗浄貯留部５０２に貯留された洗浄水を流体給排口５００から吸引し、観察窓から水滴を除去する。
