PROBLEM TO BE SOLVED: To provide a nasal cavity cannula capable of reducing an amount of supply gas which is discarded, and supplying efficiently gas into a human body.SOLUTION: A nasal cannula comprises: a main body 11 whose inner part is an airtight space； a gas introduction part 12 provided on the main body and introduces a gas supplied from a gas supply source 3 to the main body； nasal cavity insertion parts 13 each of which is provided on the main body and has elasticity of being inserted into the nasal cavity； exhaust holes 14 each of which is provided on the main body and discharges expired air from the nasal cavity to outside of the main body； and first check valves 15 each of which is provided to open and close the exhaust hole, and allows only a flow of air from inside to outside of the main body.SELECTED DRAWING: Figure 3【課題】廃棄される供給ガス量を低減し、効率良くガスを人体内に供給できる鼻腔カニューラを提供する。【解決手段】内部が気密空間とされた本体１１と、前記本体に設けられ、ガス供給源３から供給されるガスを前記本体に導入するガス導入部１２と、前記本体に設けられ、鼻腔に隙間なく挿入される弾性を有する鼻腔挿入部１３と、前記本体に設けられ、主として前記鼻腔からの呼気を前記本体の外部へ排気する排気孔１４と、前記排気孔を開閉可能に設けられ、前記本体の内部から外部への気体の流れのみを許容する第１逆止弁１５と、を備える。【選択図】図３
