A sheet feeder includes a sheet feeding unit configured to feed a sheet from a sheet storage case in a sheet feeding direction orthogonal to a loading direction in which the sheet storage case is loaded into an apparatus main body, and a conveying guide configured to guide the sheet fed by the sheet feeding unit. The conveying guide includes a first guide segment included in the apparatus main body and a second guide segment included in the sheet storage unit. The sheet feeder further includes an edge guide member disposed at an end of the first guide segment. The edge guide member has a guide surface that allows reaction force including a directional force component acting upward and a directional force component acting in a direction opposite to the sheet feeding direction to be generated when the sheet partly projecting from the sheet storage case abuts the guide surface.