A sheet feeder includes: a first roller; a separation member; a shutter; a pressing portion; and a cam portion. The separation member contacts the first roller at a contact position. An axis of the shutter is positioned downstream of the separation member in a conveying direction. The shutter is movable between first and second positions. The shutter in the first position has a portion positioned upstream of the contact position in the conveying direction. The pressing portion is positioned upstream of the separation member and the shutter in the first position in the conveying direction. The pressing portion is movable between third and fourth positions. The pressing portion in the third position faces the first roller. The pressing portion in the fourth position is separated from the first roller farther than in the third position. The cam portion is positioned upstream of the pressing portion in the conveying direction.