An original reading apparatus includes an original feeding unit for feeding the front and back sides of two-side originals in succession to a reading position, a reader unit for reading the original in the reading position, a memory unit for storing the image data of the original read by the reader unit, a read-out unit adapted to read the image data from the memory unit in the continuous order of pages, in case of reading a bundle of originals wherein the pages are so arranged that a side of the original bears the images of N-th and first pages and the other side of the original bears the images of (N-1)-th and second pages, and an output unit for successively outputting or transmitting the image data read by the read-out unit.