A document conveying apparatus includes a first conveying roller for conveying a document stacked on the document tray, a second conveying roller, provided at a downstream side with respect to the first conveying roller, for conveying a document stacked on the document tray, a separation roller, provided at a downstream side with respect to the second conveying roller, for performing separation operation of the document, a driving force transmission mechanism for transmitting the driving force to a driving shaft of the first conveying roller, a driving shaft of the second conveying roller, and a driving shaft of the separation roller, and a first blocking mechanism, provided between the first conveying roller and the driving shaft of the first conveying roller, for blocking a driving force transmitted to the driving shaft of the first conveying roller, for a first certain period of time.