Abstract: In a copying apparatus having an original carriage and an optical system, a reciprocating movement control device comprises a drive source for driving a photosensitive medium and drive transmission means effective only during forward movement to transmit the drive of the drive source to cause relative movement of the original carriage and the optical system. Righting moment accumulator means is provided for accumulating therein a righting moment with the aid of the drive source during the forward movement to cause backward movement of the original carriage or the optical system. The drive transmission means may be released by a scanning completion signal to thereby permit the righting moment accumulated in the accumulator means during forward movement to backwardly move the original carriage or the optical system and to control the speed of the backward movement.