To emake it possible to easily restore the health of a person of invalidity or with lowered immunizing capacity by setting a space wherein concentrated oxygen can be filled in a room of a general home and letting the person live in the space for a long time.

A frame with three-dimensional space is formed by fixing and assembling both end parts of a pole by fastening metal fittings and the built-in oxygen room is formed by covering a transparent or semitransparent cover with at least one entrance over whole surfaces of the frame except the bottom surface. A concentrated oxygen feeder without pressurizing mechanism is set on the outside of the portable built-in oxygen room and the concentrated oxygen is supplied into the inside of the built-in oxygen room by an oxygen feeding tube.