A device for transporting an elongated sample tube (8) into the measuring chamber (22) of an NMR magnet system comprising a spinner which has an axial through-bore through which the sample tube can be inserted, transported together with the spinner on an air cushion into the measuring chamber, and positioned therein relative to the vertical axis of the NMR receiver coil system (9) is characterized by a mounting sleeve (17) which is disposed in a collar-like manner radially around the sample tube such that it cannot slip and which, in the operating position of the sample tube, flatly abuts with one end face thereof on a horizontal stop surface (18) in the bottom region inside a two-stage axial bore (20) of the spinner (7b), wherein the inner diameter of the bore (20), in a first stage in the upper region, is larger than the outer diameter of the mounting sleeve, and the inner diameter of a second stage, in the bottom region of the spinner, is smaller than the outer diameter of the mounting sleeve but larger than the outer diameter of the sample tube. This permits modification of a transport device for NMR measuring capillaries using simple technical means such that it is less sensitive than the conventional devices to curtail breakage of glass.