PROBLEM TO BE SOLVED: To provide an endoscope system of a simple structure which prevents a window on its insertion section from getting dirty or clouded by always forming a gas curtain over the window surface without complicating operations.SOLUTION: This endoscope system includes: an air supply passage 20 installed at a sheath insertion section covering the insertion section of the endoscope a nozzle 68 provided at the distal end of the insertion section of the sheath an air supply tube 62 placed between a gas cylinder 100 and the air supply passage 20 to guide a gas from the gas cylinder 100 to the air supply passage 20 a depressurizing unit 106 and a flow rate controller 112 for limiting the pressure or flow rate of the gas supplied from the gas cylinder 100 the air supply tube 64 for guiding the gas whose pressure or flow rate has been controlled by the depressurizing unit 106 or the flow rate controller 112 to the air supply passage 20 and an switching mechanism 124 provided only on the air supply tube 62 of the air supply tubes 62 and 64, with which the gas supplying to the air supply passage 20 can be selectively started or stopped.COPYRIGHT: (C)2013,JPO&INPIT【課題】簡易な構成で操作を複雑にすることなく、内視鏡挿入部の窓部の表面にガスカーテンを常時形成し、窓部の汚れや曇りを未然に防止する。【解決手段】内視鏡挿入部を外装するシース挿入部に設けられた送気管路20と、シース挿入部の先端に設けられたノズル68と、ガスボンベ100と送気管路20との間に設けられ、ガスボンベ100から供給されるガスを送気管路20に導く送気チューブ62と、ガスボンベ100から供給されるガスの圧力又は流量を制限する減圧ユニット106及び流量調整部112を有し、前記減圧ユニット106及び流量調整部112によって圧力又は流量が制限されたガスを送気管路20に導く送気チューブ64と、送気チューブ62、64のうち、送気チューブ62のみに設けられ、送気管路20へのガスの供給及び停止を選択的に切り替える操作機構124とを備えた内視鏡システムを提供する。【選択図】図4
