A sheet feeder is provided. The sheet feeder includes a sheet container installation space forming member to form a sheet container installation space in the sheet feeder; a sheet container to contain a recording sheet therein, which can be inserted into or extracted from the sheet container installation space; and a sheet feeding device, which contacts with the recording sheet in the sheet container at a sheet pickup position to apply a feeding power to the recording sheet. The sheet feeder has a passage, which is formed by the sheet container and the sheet container installation space forming member to communicate the inside of the sheet feeder with the outside thereof and which is detoured plural times, wherein the passage is located above the sheet pickup position.