An aerating device includes a frame, moving means arranged on the frame for moving the aerating device in a direction of movement over a ground surface for working, a drive, a rotor shaft provided with a plurality of knives, where the rotor shaft is arranged bearing-mounted between the frame and the drive and is operatively coupled to the drive for rotating the rotor shaft, and where the knives are inserted successively into the around surface, and where during uncoupling of the rotor shaft and the drive the rotor shaft is movable in a direction away from the drive such that the rotor shaft lies at a distance from the drive.