A radiation-shielding container comprising an outer plastic tube, an inner radiation-shielding metal tube inserted into the outer tube and a top plastic cap accompanied with a plug made of a radiation-shielding metal on its back and a bottom plastic cap, wherein the top and the bottom caps attach to the uppermost and the lowermost edges, respectively of the plastic outer tube in a snap-on method or a screwed or threading method, have respectively a peripheral thin section on the curved surface and are so designed that they can not be removed from the outer tube unless the thin section of the cap is cut off or that the thin section is forcibly opened.