A document feeder includes a conveying path extended from a document supplying position to a reading position, a first conveying roller pair provided upstream from the reading position and nipping and conveying the document, a second conveying roller pair provided downstream from the reading position and nipping and conveying the document faster than the first conveying roller pair, a post-reading conveying path extended downstream from a nipping position of the second conveying roller pair, the post-reading conveying path being located above a plane tangent to the second conveying roller pair at the nipping position running in a reverse sheet feed direction, and a third conveying roller pair provided on the post-reading conveying path and nipping and conveying the document conveyed from the second conveying roller pair at a conveying force equivalent to that of the second conveying roller pair.