A sheet feeder, including: a holding portion for holding sheets; a sheet supply portion; an inclined member disposed downstream of the holding portion and having an inclined surface for guiding each sheet in a sheet feed direction along the inclined surface; a plurality of first separation protrusions provided on and integrally with the inclined member and arranged in the sheet feed direction, each first separation protrusion protruding from the inclined surface such that its distal end is located more downstream in the sheet feed direction than its proximal end; and a plurality of second separation protrusions formed of a metal, each second separation protrusion protruding from the inclined surface through a corresponding one of openings formed in the inclined member at a position in the sheet feed direction between corresponding adjacent two of the first separation protrusions, the second separation protrusions being arranged in the sheet feed direction.