Measuring device for determining torques which act on a shaft (5, 6) having a torsionally relevant shaft section, in particular a drivetrain of a motor vehicle, wherein the measuring device comprises: - two magnetically conductive topographies (20, 21, 20', 21') connected non-rotatably with the shaft (5, 6), which are rotatable depending on the torsion; - two rotationally symmetrical rotary flywheel masses (1, 2), between which the torsionally relevant shaft section is situated and on which the magnetically conductive topographies (20, 21, 20', 21') are disposed lying opposite spaced by an air gap; - a magnet which is oriented between the rotary flywheel masses (1, 2) such that the generated magnetic field lines follow the preferred course from the middle point of one of the rotary flywheel masses to the outer edge and close the magnetic circuit over the oppositely-situated rotary flywheel mass and the topographies there; - at least one magnetic field sensor which serves to measure a field behaviour of the magnetically conductive topographies, which are conductively connected with a magnetic field, and which is fixed in stationary manner such that the magnetic field lines in the outer circumference of the rotary flywheel masses are measurable; - electronic means connected downstream for determining the acting torques depending on the phase relation between the magnetically conductive topographies, - electronic evaluation means which serve to take into consideration an electrical signal generated out of the magnetic field strength only above and below given threshold values such that in the result only a rectangular signal profile is formed, to determine a duty cycle of the rectangular signal profile and from the duty cycle to deduce the phase relation between the topographies. - two magnetically conductive topographies (20, 21, 20', 21') connected non-rotatably with the shaft (5, 6), which are rotatable depending on the torsion; - two rotationally symmetrical rotary flywheel masses (1, 2), between which the torsionally relevant shaft section is situated and on which the magnetically conductive topographies (20, 21, 20', 21') are disposed lying opposite spaced by an air gap; - a magnet which is oriented between the rotary flywheel masses (1, 2) such that the generated magnetic field lines follow the preferred course from the middle point of one of the rotary flywheel masses to the outer edge and close the magnetic circuit over the oppositely-situated rotary flywheel mass and the topographies there; - at least one magnetic field sensor which serves to measure a field behaviour of the magnetically conductive topographies, which are conductively connected with a magnetic field, and which is fixed in stationary manner such that the magnetic field lines in the outer circumference of the rotary flywheel masses are measurable; - electronic means connected downstream for determining the acting torques depending on the phase relation between the magnetically conductive topographies, - electronic evaluation means which serve to take into consideration an electrical signal generated out of the magnetic field strength only above and below given threshold values such that in the result only a rectangular signal profile is formed, to determine a duty cycle of the rectangular signal profile and from the duty cycle to deduce the phase relation between the topographies.