PURPOSE: To provide the both-FACE scanner which can reduce the number of parts and can shorten reading time.

CONSTITUTION: Reading is started when a first optical unit 5 is placed at a sub scanning start position A on the side of one face 1a of an original 1 and a second optical unit 8 is placed at a sub scanning end position C on the side of another face 1b. Image information on the side of 1a is read until moving to a sub scanning end position B by transmitting the driving force of an optical unit driving part 10 through a timing belt 12 and a pulley group 11 in the state of selecting an incidental optical path with an optical path switching part 4 and making reflected light La incident to a photoelectric conversion part 2. During this reading, the second optical unit 8 engaged to the timing belt 12 is moved to a sub scanning start position D on the side of the other face 1b. Next, image information on the side of 1b is read until moving the second optical unit 8 to the sub scanning end position C in the state of making reflected light Lb on the side of the other face 1b incident to the photoelectric conversion part 2 with a mirror 7 and a mirror group 9 by using the optical path switching part 4, and the first optical unit 5 is returned to the position A.