A sheet feeder is provided that includes a driving roller, a driven roller configured to rotate in accordance with rotation of the driving roller and feed a sheet while pinching the sheet with the driving roller, an elastic shaft inserted through the driven roller and configured to rotatably support the driven roller, the elastic shaft including a protrusion formed on at least one end of the elastic shaft in an axial direction of the elastic shaft, the protrusion protruding outward in a radial direction of the driven roller, and two recess-shaped bearings configured to support two end portions of the elastic shaft in the axial direction, respectively, at least one of the bearings including a contact surface configured to contact the protrusion when the elastic shaft is supported by the bearings.