PROBLEM TO BE SOLVED: To provide a lens washing sheath for an endoscope that includes a tip constituting part at the tip part of an insertion part, can wash the whole surface of an objective lens by making a fluid jetted from a fluid jet port to an internal space surrounded by a wall part into a vortex flow of a predetermined force, and discharge the fluid in the internal space after the washing so that good endoscope observation can be performed.SOLUTION: A washing sheath 10 includes a tip constituting part 30 fixed to the tip part of a multi-lumen tube 20 for coating an insertion part 2 of an endoscope 1, a wall part 80 having an internal wall surface 81 that protrudes to a front side from a distal end surface 7f and surrounds the distal end surface 7f in a state where a distal end part 7 is disposed in the tip constituting part 30, a fluid jet port 71 provided to the internal wall surface 81, which regulates a jet direction so that the fluid can flow toward a partial region of the surface of an observation window 7a, a deflection surface 82 for deflecting a flow direction so that the fluid can flow toward another region of the observation window 7a when the fluid collides, and a fluid discharge part 83 for discharging the fluid jetted to an internal space S surrounded by the wall part 80.SELECTED DRAWING: Figure 6C【課題】挿入部の先端部に先端構成部を配置して、流体噴出口から壁部に囲まれた内部空間に噴出された流体を所定の流勢の渦流にして対物レンズ表面全体の洗浄が可能で、洗浄終了後には内部空間内の流体を排出して良好な内視鏡観察が行える内視鏡用レンズ洗浄シースを提供する。【解決手段】洗浄シース10は、内視鏡1の挿入部2を被覆するマルチルーメンチューブ20の先端部分に固設される先端構成部30と、先端構成部30に先端部7が配置された状態おいて先端面7fより前方側に突出し先端面7fを囲む内壁面81を有する壁部80と、内壁面81に設けられ、観察窓7aの表面の一部の領域に向かって流体が流れるように噴出方向を規定した流体噴出口71と、流体が衝突することによって観察窓7aの他の領域に向かって流れるように流れ方向を偏向させる偏向面82と、壁部80に囲まれた内部空間S内へ噴出された流体を排出する流体排出部83と、具備する。【選択図】図6C
