The present invention relates to a duplex scanning apparatus. The duplex scanning apparatus includes a scanning module, a sheet input tray, a sheet ejecting tray, a transfer channel, a sheet pick-up roller, a friction-enhancing stopper, a transfer roller assembly, a sensor, a first inverting region, a second inverting region, an inverting channel, a sheet ejecting roller assembly, a first inverting roller assembly, a second inverting roller assembly, a first switching element and a second switching element. By providing two inverting regions, the scanning time for performing a duplex scanning operation by the duplex scanning apparatus of the present invention is shortened.