Abstract: In the method and the apparatus for measuring and controlling the roll gap in a roll stand the roll gap is illuminated by a light source transversely of the roll axis or also parallel to the roll axis. A camera, in particular a CCD line camera, is aligned with its optical system with the roll gap and the illuminated part of the gap is broken down in this camera in the direction of the height or thickness of the gap into image points which generate on illumination an electrical charge, the image points being consecutively periodically interrogated for bright-dark information by drive electronics and the sum of the bright or dark light points serving as information on the magnitude of the roll gap and for controlling the roll gap setting.