Abstract: An apparatus for regulating welding parameters during laser beam welding includes a camera for detecting the geometry of a melt bath formed during the welding process. The camera is connected with an image-data-processing unit. The welding depth is regulated by the processing unit as a function of the detected melt bath length or melt bath area. The focus position of the laser beam is regulated as a function of the geometric similarity factor, which is calculated as the quotient of the melt bath area and the distance between the geometric centers of gravity of the laser beam keyhole and the melt bath area. Detection and regulation of gaps between the workpieces of height offset between the workpieces and/or lateral offset of the laser beam is also provided for.