To solve a trouble that connecting of a hose is released in an emergency and the problem whether oxygen can be secured in a course of shelter, although in using of an oxygen cylinder, it is necessary to give attention to a residual amount of oxygen gas in the cylinder and exchange the used cylinder with a cylinder packed with oxygen gas when oxygen gas in the cylinder is thoroughly used, and then in using a PSA method and a membrane separation method, it is necessary to always make equipment one size larger as an amount of pressure drop by a hose.

A feeding apparatus of oxygen gas is arranged with a gas-separation hollow-fiber membrane 50 for separating a wet oxygen-rich gas having a high concentration by introducing a compressed air and a carbon dioxide absorbing tank 70 for removing the carbon-dioxide gas contained in the oxygen rich gas.