Use of an inline measuring device designed to measure at least a measured variable, particularly a physical measured variable, particularly a mass flow, a density and/or a viscosity of a medium conducted in a pipe, and designed to map the at least one measured variable to a measured value signal currently representing said measured variable, as well as an apparatus designed for the temperature-control of the inline measuring device, - wherein the inline measuring device comprises a vibronic-type sensor, particularly accommodated within a sensor housing (6, 7), - and wherein the apparatus comprises: -- at least a first heat exchanger fixed on the inline measuring device, wherein temperature-control fluid designed to transport heat flows through said heat exchanger during operation, as well as -- fastening elements (50, 60) designed to fix the at least first heat exchanger on the outside of the inline measuring device, particularly in a detachable manner -- wherein the heat exchanger has an interior wall, particularly curved in the form of a channel or shell, which is in at least partially in contact with the inline measuring device from the outside over a large surface area, as well as an exterior wall fixed on said interior wall; characterized in that the exterior wall is connected to the interior wall - via a marginal connecting seam which is leak-tight in relation to the temperature-control fluid and extends along a marginal area, as well as via a multitude of internal connection points, particularly punctiform or annular, which are arranged at a distance from one another in an interior area that is at least partially enclosed by the marginal connecting seam - in such a way that at least a cavity is formed between the interior wall and exterior wall, said cavity having several sections that communicate with one another and serving to conduct the temperature-control fluid, wherein the cavity is integrated into a temperature-control pipe system that conducts the temperature-control fluid by means of openings (33A, 34A) that enter into the cavity. - wherein the inline measuring device comprises a vibronic-type sensor, particularly accommodated within a sensor housing (6, 7), - and wherein the apparatus comprises: -- at least a first heat exchanger fixed on the inline measuring device, wherein temperature-control fluid designed to transport heat flows through said heat exchanger during operation, as well as -- fastening elements (50, 60) designed to fix the at least first heat exchanger on the outside of the inline measuring device, particularly in a detachable manner -- wherein the heat exchanger has an interior wall, particularly curved in the form of a channel or shell, which is in at least partially in contact with the inline measuring device from the outside over a large surface area, as well as an exterior wall fixed on said interior wall; -- at least a first heat exchanger fixed on the inline measuring device, wherein temperature-control fluid designed to transport heat flows through said heat exchanger during operation, as well as -- fastening elements (50, 60) designed to fix the at least first heat exchanger on the outside of the inline measuring device, particularly in a detachable manner -- wherein the heat exchanger has an interior wall, particularly curved in the form of a channel or shell, which is in at least partially in contact with the inline measuring device from the outside over a large surface area, as well as an exterior wall fixed on said interior wall;