A device for an interferometric measuring device having a first interferometer and a second interferometer, short coherent radiation being supplied to the first interferometer via a radiation source which is split into to beam components by a first beam splitter; and the optical path length in a beam component being longer than in the other beam component to the effect that the optical path difference is greater than the coherence length of the radiation; before emerging from the first interferometer, the two beam components being recombined and supplied to the second interferometer, which splits the radiation into two additional beam components; the optical path lengths of the two beam components being different to the effect that the optical path difference registered in the first interferometer is balanced again; the optical path length for the respective beam component in the first and the second interferometer being able to be set by at least one movable optical component, and the movable optical components are coupled to each other mechanically. A method for balancing an optical path difference in such an interferometric measuring device, the optical path differences between the beam components being changed in the two interferometers by mechanically coupled movable optical components at the same time and by the same absolute amount. By doing this, path differences in the beam components of the interferometers are able to be varied in one working step, the conditions for the formation of interference being complied with.