A conveying device in or for an apparatus for administering a product, including a base, a first conveying member which can be moved relative to the base and includes a first thread, a second conveying member which can be moved relative to the base and includes a second thread for a threaded engagement with the first thread, wherein the second thread extends over an axial portion of the second conveying member which is radially flexible in relation to its threaded axis, such that one of the conveying members can be axially inserted into the other in an overlap of the threads, and a blocking member which can be moved relative to the base, wherein one of the blocking member and the second conveying member can be moved relative to the other into a blocking position in which the blocking member radially stiffens the second thread in the threaded engagement in the region of the flexible axial portion and thus secures the threaded engagement.