PURPOSE: To readily convert the lateral sheet-aligning means from one side to the other without play and with little cost in a machine for printing on both sides of the sheet with double feeding of a sheet pile.

CONSTITUTION: Device for conveying and aligning sheets on a feed table of a printing machine having a single-sheet feeder, an aligning section, and a revolving conveying roller for conveying the sheets, wherein an aligning member adjustably and rotatably support the lateral position above the feed table, comprises stopper plates 3 on both the sides for alternately aligning the supplied sheets 27. The sheets 27 to be aligned are moved by a conveying roller 23 against the stopper plates, the conveying roller is movably driven by a multiple cam 15, and the sheets 27 to be aligned are contacted to one or the other stopper plates 3 in the lateral direction by the conveying roller 23.