A turning device uses a turning bar for diverting a material web. The turning bar includes a sleeve with a plurality of holes and an inner chamber that is supplied with compressed air, as well as a closing body. The turning bar is supported by a frame and is able to pivot through 90.degree.. The closing body is movable within the inner chamber in response to this pivoting movement of the turning bar. Movement of the closing body closes one of two groups of the holes, depending on the position of the turning bar. The turning bar is connected to the frame at only one end and is supplied with compressed air through a joint connecting the turning bar to the frame.