Relatively high stabilized the humidifier of the medical application gas which can offer the medical application gas which humidifies on patient side is offered. It possesses the container which possesses the water territory which stays the water for the humidification which is divided inside the container which is provided in liquid denseness airtightness by the gas selective permeable membrane and the gas territory because it stays the medical application gas from medical application gas supply expedient, the water storage section in order the aforementioned water territory is arranged in the position where it is higher than the aforementioned humidifier the medical gas which stays in the aforementioned gas territory with the vapor which evaporates from aforementioned water territory humidifying, in the humidifier of the medical application gas which forces the medical application gas which is humidified to patient side, and to the humidifier to supply the water of place fixed quantityExtending to the gas stay space of top of the water storage section of the water supply container and the aforementioned water container which it possesses we have possessed the water inlet in order to connect the pressure adjustment tube to liquid denseness airtightness, the gas territory has had the gas outlet in order to force the medical application gas which is humidified to patient side, and furthermore the occasion where gas pressure of the excessive medical application gas is loaded inside the humidifier, it has possessed the connected mouth in order to connect the pressure adjustment tube in order to reset the aforementioned excessive pressure into the aforementioned water supply container.< Selective figure > Figure 1比較的高く安定した加湿した医療用ガスを患者側に提供できる医療用ガスの加湿器を提供する。液密・気密に設けられた容器内をガス選択透過性膜により仕切られた加湿用の水を滞留させる水領域と、医療用ガス供給手段からの医療用ガスを滞留させるためのガス領域を有する容器を有し、前記水領域から気化した水蒸気により前記ガス領域に滞留する医療ガスを加湿して、加湿された医療用ガスを患者側へ圧送する医療用ガスの加湿器において、前記水領域は、前記加湿器よりも高い位置に配置され、そして加湿器へ所定量の水を供給するための水貯留部を有する水供給容器と前
