Abstract: Device for checking of flatness and smoothness of an item (10) comprising components for measuring of flatness with an interference method and for measuring of smoothness with a reflection method, where the item (10) or a mirror (23) close to the item can be tilted in two directions until stripes of an interference pattern created on a first image plane (14) have a predetermined distance and a predetermined general direction, the deviations from flatness being calculated from the distance and curvature of the stripes, and the smoothness being calculated from the brightness variations in the mirror image created by the reflection method on a second image plane (22).