An image input device 1 includes a rotating roller 4 supported so as to be freely rotatable around a rotational axis thereof, wherein the roller 4 includes a line image sensor 3 and a Selfoc lens array 6 which are mounted not to rotate in the rotating roller 4 by a holder 51. The holder 51 functions as a light guide to introduce the light emitted from light emitting elements 52 to a finger 200 which is pressed against the peripheral surface of the rotating roller 4. Selfoc lens array 6 forms a one-dimensional optical image of the portion of the finger 200 which is in contact with the peripheral surface of the rotating roller 4, on the line image sensor 3, so that the line image sensor 3 obtains the one-dimensional optical image. Then, the one-dimensional optical images are combined by a composite buffer 15 in order, to create a two-dimensional optical image of the finger 200.