The drive device, which serves for the transport of the cover of a liquid container, particularly a swimming pool, is installed or installable in device compartment, which is arranged separate from the liquid container. The drive device includes at least one winding shaft that interacts with the cover and that is coupled to a first drive unit. The winding shaft serves for the rolling-up of the cover, which can be guided over a deflection device to an outlet opening of the device compartment and, at the end facing the winding shaft, is connected to an outer tractive element, which is acting against the side of the cover that is opposite to the side which faces the deflection device, which outer tractive element presses the cover under tension against the deflection device, and which outer tractive element is held and can be tensioned by a first traction device.