A measuring device for the optic measuring of an object 13a is provided, in particular for measuring a motion of the object. The device includes an interferometer 20 with a measuring beam exit 12, a reflection beam entry 14, an interfering beam exit 15, and a light source 1 for creating a light beam 8, an optic detector 16, which is arranged at the interfering beam exit 15 of the interferometer 20 such that a light beam exiting the interfering beam exit 15 impinges the detector and a signal processing unit 17 connected to the detector 16 being embodied such that they can measure measuring signals of the detector 16. The interferometer (20) is provided with a switched beam entry (18) and is embodied such that dependent on a switching signal connected to a switched beam entry (18) a light beam exits the measuring beam exit (12) essentially with a predetermined light intensity and at a predetermined angle, and that the signal processing unit (17) is provided with a switched beam exit, which is connected to the switched beam entry (18) of the interferometer, with the signal processing unit (17) controlling the interferometer such that a light beam exits the measuring beam exit (12) only during the measuring of measuring signals essentially with a predetermined light intensity and at a predetermined angle.