Device for billboards of the kind where the board has a hard firm surface to which the message can lie close, where the message is arranged in several lengths placed beside each other whose height is the same as that or the board, where the lengths overlap each other in their side edges and where every length belonging to the message can be put up and taken down separately, characterized by the fact that for each length there is a hoisting device mounted on the board on which the upper edge of the length can be applied when the hoisting device is in its lowest position near the lower edge or the board and that the hoisting device after that can be hoisted to its uppermost position with the length applied and in this position keep the length.