An apparatus for variable setting of control times of gas exchange valves of an internal combustion engine which has a drive element an output element and a side cover. The drive element is brought into drive connection with a crankshaft, the output element is brought into drive connection with a camshaft, and the output element is arranged such that it can be pivoted with respect to the drive element. The side cover, which has a sealing cover with an opening and a mating element, axially delimits the output element and/or the drive element, and is connected in a rotationally fixed manner to the drive or output element by means of a fastening element. The fastening element reaches at least partially through the opening and interacts with the fastening element producing a rotationally fixed connection between the side cover and output element or drive element.