Abstract: A screw-driving device includes a casing having a slide member which in turn supports an indexing arrangement for indexing a flexible belt carrying a plurality of screws, the indexing arrangement serving to index a screw into a screwing station whenever the device is operated. The index arrangement includes sprocket discs the teeth of which engage the notched belt and movement of the indexing device to index the belt through one pitch is controlled by a coupling movable under the control of a pin slidable in an elongate aperture or recess in the casing of the device.A plurality of springs is employed to return the slide member to its inoperative condition at the end of each working cycle.