[en] Object: To lock radioactive rare gases as the surrounding compounds to thereby safely and securely store them for a long period of time. Structure: The radioactive rare gases separated from waste gases by the low temperature adsorbing device or the like are once stored in a gas holder and when they reach a given level of storage, they are introduced under pressure by a pressurizing machine into a reaction vessel containing hydroquinone aqueous solution and dissolved sufficiently. Then, the hydroquinone aqueous solution is gradually cooled by a temperature controller to room temperature to thereby separate the surrounding compound. Thereafter, the radioactive rare gases remained within the reaction vessel and piping are recovered into the gas holder by means of a suction pump and then, the surrounding compound is separated from the solution and sealed into a storing container for a long period of time. (Kamimura, M.)