An apparatus for detecting a pre-aligning element at a wafer and a method for pre-aligning a wafer are disclosed. In an embodiment, the apparatus includes a sensor arrangement configured to illuminate subsequent edge portions of the wafer edge and to output a first and a second sensor signal, wherein the first sensor signal is based on the transmitted fractions of the illumination and the second sensor signal is based on the reflected fractions of the illumination; and an evaluation unit configured to evaluate the first sensor signal and to determine a first position information indicating a coarse position of the pre-aligning element, and, after having determined the first position information, to determine a second position information based on the second sensor signal and the first position information, wherein the second position information indicates a fine position of the pre-aligning element.