Measuring sensor, comprising: an oscillator with at least one measuring tube (10.1, 10,2) for guiding a medium; only one exciter arrangement for exciting the oscillator to bending oscillations of the at least one measuring tube (10.1, 10, 2); at least one sensor arrangement on the inlet side for detecting the bending vibrations of the at least one measuring tube (10.1, 10, 2); and at least one sensor arrangement on the outlet side for detecting the Bending vibrations of the at least one measuring tube; and a measuring and operating circuit which set up to control the exciter arrangement with an excitation signal, and to detect sensor signals from the inlet-side and outlet-side sensor arrangements (12a, 12b), and to determine a measured density value and/or a measured mass flow rate value on the basis of the sensor signals, the exciter arrangement having a first exciter assembly (11.1), which is fastened to the at least one measuring tube (10.1), and a second exciter assembly (11.2), with respect to which the at least one measuring tube is to be excited to oscillate, the first exciter assembly (11.1) having a center of gravity which, apart from manufacturing tolerances, lies in a measuring tube transverse plane which extends perpendicularly to the at least one measuring tube (10.1, 10.2), and with respect to the second exciter assembly (11.2) the at least one measuring tube (10.1, 10.2) is to be excited to oscillate. in which the at least one measuring tube (10.1, 10.2) has a substantially mirror-symmetrical course; wherein the exciter arrangement comprises an electrodynamic exciter and at least one equalizing mass body (19.1, 19.2), wherein the electrodynamic exciter is arranged to exert an excitation force on the at least one measuring tube (10.1, 10.2), the between the first and second exciter assemblies (11.1, 11.2), whereby an effective center of the excitation force is located outside the transverse plane of the measuring tube, wherein the first exciter assembly (11.1) comprises a magnet, the second exciter assembly (11.2) comprising a coil (18.2) arranged to generate an alternating magnetic field with which the magnet (18.1) interacts to generate the oscillations of the first exciter assembly (11.1). measuring tube (10.1, 10.2); characterized in that the first exciter assembly (11.1) has a carrier body (15.1) on which the magnet (18.1) and the compensating mass (18.2) are arranged, the carrier body (15.1) being designed symmetrically with respect to the transverse plane of the measuring tube; and the first exciter assembly (11.1) by means of a joint at the at least one measuring tube (10.1) is attached, with the transverse plane of the measuring tube running through the joint. an oscillator with at least one measuring tube (10.1, 10,2) for guiding a medium; only one exciter arrangement for exciting the oscillator to bending oscillations of the at least one measuring tube (10.1, 10, 2); at least one sensor arrangement on the inlet side for detecting the bending vibrations of the at least one measuring tube (10.1, 10, 2); and at least one sensor arrangement on the outlet side for detecting the Bending vibrations of the at least one measuring tube; and a measuring and operating circuit which set up to control the exciter arrangement with an excitation signal, and to detect sensor signals from the inlet-side and outlet-side sensor arrangements (12a, 12b), and to determine a measured density value and/or a measured mass flow rate value on the basis of the sensor signals, the exciter arrangement having a first exciter assembly (11.1), which is fastened to the at least one measuring tube (10.1), and a second exciter assembly (11.2), with respect to which the at least one measuring tube is to be excited to oscillate, the first exciter assembly (11.1) having a center of gravity which, apart from manufacturing tolerances, lies in a measuring tube transverse plane which extends perpendicularly to the at least one measuring tube (10.1, 10.2), and with respect to the second exciter assembly (11.2) the at least one measuring tube (10.1, 10.2) is to be excited to oscillate. in which the at least one measuring tube (10.1, 10.2) has a substantially mirror-symmetrical course; wherein the exciter arrangement comprises an electrodynamic exciter and at least one equalizing mass body (19.1, 19.2), wherein the electrodynamic exciter is arranged to exert an excitation force on the at least one measuring tube (10.1, 10.2), the between the first and second exciter assemblies (11.1, 11.2), whereby an effective center of the excitation force is located outside the transverse plane of the measuring tube, wherein the first exciter assembly (11.1) comprises a magnet, the second exciter assembly (11.2) comprising a coil (18.2) arranged to generate an alternating magnetic field with which the magnet (18.1) interacts to generate the oscillations of the first exciter assembly (11.1). measuring tube (10.1, 10.2); characterized in that the first exciter assembly (11.1) has a carrier body (15.1) on which the magnet (18.1) and the compensating mass (18.2) are arranged, the carrier body (15.1) being designed symmetrically with respect to the transverse plane of the measuring tube; and the first exciter assembly (11.1) by means of a joint at the at least one measuring tube (10.1) is attached, with the transverse plane of the measuring tube running through the joint.