A measuring device for detecting a relative position, the measuring device including a measurement graduation movable in at least one measurement direction and a scanning unit for determining a relative position of the measurement graduation with respect to the scanning unit. The scanning unit includes a light source, a scanning grating disposed on a first side of a transparent carrier element that is positioned in a scanning beam path and a detector arrangement. The scanning unit further includes an attenuation structure that adjusts a light intensity on the detector arrangement in a defined manner, wherein either 1) the attenuation structure is disposed on a second side, opposite the first side, of the transparent carrier element or 2) the attenuation structure has a permeability that varies as a function of location at least along one direction so that a light intensity which is uniform at least in that one direction results on the detector arrangement.