A sheet conveying device for an image forming apparatus of the present invention includes a cover hinged to the casing of the apparatus and supporting a roller shaft on which a drive roller is mounted. A driven roller and a positioning section for positioning the drive roller are mounted on the casing. The cover is movable between a closed position where the drive roller is pressed against the driven roller and an open position where the former is released from the latter. A first drive gear is affixed to the end of the roller shaft while a second drive gear, meshing with the first drive gear, is mounted on the cover and receives the output torque of a drive source. The roller shaft is mounted on the cover such that the pitch circle of the first drive gear moves on the pitch circle of the second drive gear while touching it externally.