The invention concerns a conveying device for sheet steel plates and for moving several sheets (1, 1') inside or through a working zone (W; 50) wherein the sheets are machined. The inventive feeding device comprises first and second sheet feeders (10, 11; 20) which feed the sheets in controlled manner to the working zone (W) so that the sheets are machined with positional accuracy. The first sheet feeder (10, 11) is located on an input side of the tool zone and the second sheet feeder (20) is located on an output side of the tool zone. The two sheet feeders (10, 20; 11; 20) are mutually synchronized in their movements (x, y) when feeding forward the sheet (1), the sheet driven by the synchronous movement being maintained by the two sheet feeders. The invention provides the advantages of increased speed and safety. It is possible to increase the speed without the sheet being deformed or losing its flatness.