The invention relates to a belt run control device of an endless belt (2) revolving over at least one cylindrical roller (1), wherein the rollers (1) are each designed as deflection rollers around which the belt (2) is wrapped, and wherein for the purpose of tensioning the belt (2) at least one cylindrical roller (1) is preloaded on both sides by way of elastic elements (3) designed to be equally acting in order to center the belt (2) relative to the roller (1), and wherein a position measuring device is provided in the region of the belt (2), wherein an adjusting element (5) that can be actuated using a pneumatic piston-cylinder unit (4) is disposed on at least one side of the roller (1), characterized in that the adjusting element (5) is designed to apply a force that acts additively or subtractively with respect to the preloading force of at least one of the elastic elements (3).