A sheet feeder includes: an attraction separation unit including an attraction belt stretched between rollers and facing the upper surface of a sheet bundle to attract an uppermost sheet thereof, rotatably supported by a support member at a position upstream of the attraction belt in a sheet feeding direction, and supporting the rollers to be released from the support upon contact of the rollers with the uppermost sheet via the attraction belt; and a swing device for swinging the attraction separation unit around the support member as a pivot to move the attraction belt between an attraction position and a feed position more distant from the sheet bundle than the attraction position, and swinging, after the uppermost sheet has been attracted to the attraction belt at the attraction position, the attraction belt to the feed position to be rotated to feed the uppermost sheet.