A sheet feeder includes: a sheet feeding assembly including: a shaft having an insertion part; and a feed roller; and a main body including: a rotary part; and first and second bearings. The main body supports the sheet feeding assembly. The rotary part rotates upon transmission of a drive force and receives the insertion part. The bearings support the shaft. An opening of an open portion of the first bearing has a circumferential dimension greater than a diameter of the shaft. The shaft supported by the bearings is movable between a mounted position and a retracted position. The feed roller is supported by the shaft, and movable as the shaft moves between the mounted position and the retracted position. The insertion part is separated from the rotary part when the shaft is in the retracted position, and inserted into the rotary part to place the shaft in the mounted position.