An apparatus for driving a scanner includes a driving motor which is rotated in both directions, a driving gear which is driven by the driving motor, a driving pulley which rotates a timing belt coupled to the scanner body, a reduction gear which is engaged with a gear portion of the driving pulley, a power transmitting unit for directly transferring a rotational force of the driving gear to the driving pulley or transferring the rotational force through the reduction gear to the driving pulley, where, when reading a colored image, the driving force is decelerated and then transferred to the driving pulley under the same speed of the driving motor as a case of reading a black-and-white image, in accordance with the rotating direction of the driving motor.