In the sheet feeder, a first intermediate gear support shaft is inserted into a bearing of a first intermediate gear, and contains a bearing engaging part including a sectional shape having a substantial D-shaped cut having a flat part and a circular part. The bearing engaging part having a substantial D-shaped cut of the first intermediate gear support shaft contains two support parts and located on the boundary line between the flat part and the circular part. The support parts are arranged so as to support the circular bearing of the first intermediate gear at two positions sloping by a predetermined angle right and left for the line of a force which passes the center of the first intermediate gear and is applied to the first intermediate gear from the rotation. The support parts have a chamfered or rounded shape.