An automatic original document conveying apparatus conveys a placed original document to a prescribed position and delivers the original document. The automatic original document conveying apparatus includes a resin frame, an original document feeding unit for sequentially feeding an original placed document, an original document delivering unit for delivering the fed original document and a metal support plate thereof. The metal support plate securely connects in a united body the resin frame, the original document feeding unit and the original document delivering unit so as to maintain respective relative assembled positions of the units.