Abstract: A method and apparatus for connecting a tube coaxially arranged around a measuring probe in a measuring probe unit of a fill-level measuring device comprising: a cable- or rod-shaped measuring probe and a tube coaxially surrounding the measuring probe. The measuring probe unit is connected to the container by means of a process connection element, wherein the measuring probe and the tube arranged coaxially around the measuring probe for the measuring probe unit are connected releasably to the process connection element. The coaxially arranged tube is connected releasably to the process connection element via a shape interlocking, threaded connection in a defined connection region, and the releasable, shape-interlocking, threaded connection of the coaxially arranged tube to the process connection element is secured by means of a radially directed deformation of the coaxially arranged tube in the defined connection region.