To provide a sheet material feeder that can evenly feed sheet materials without their slips and damaging their quality and while preventing their meandering.

Either workpiece inlet or outlet end of a working machine has upper-lower pairs of rollers 11 and 12 rotatable with a sheet material 100 in between to feed it, and a width guide member 13 for enclosing both side edges of the sheet material 100 at least from below to guide it, both which elements are integrated together. Both or either of the rollers 11 and 12 is externally roughened and is positioned to grip the portion of the sheet material 100 except machining areas 102 and to feed the sheet material 100 evenly without slips, meandering and flexure.