Abstract: The invention concerns a filling level measuring device composed of a nonmagnetic slide tube (7) containing a switch (8) driven magnetically in contactless manner and mounted on a plate (1) sealing a container aperture, further of a float (23) displaceably resting on the slide tube (7) and fitted with a first permanent magnet (24) actuating the switch (8). The float (23) of this invention further includes a second permanent magnet (25) a distance from the permanent magnet (24) associated to the switch (8), this second permanent magnet (25) resting by its own magnetic field on the magnetic field of an oppositely polarized permanent magnet (15) affixed to the slide tube (7). A magnetic coil (17) is affixed to the slide tube (7) which when energized generates a magnetic field reinforcing the effect of the oppositely polarized magnetic field and is of such field intensity that the float (23) is lifted into the switching position without being supported by buoyancy.