PURPOSE: To reduce the size of a driving source necessary for scanning by forming the reflecting mirror of an exposure lamp and its stand of light alloy in one body and providing a lamp which extends in the same direction as the extension direction of the reflecting mirror at the focus part of the reflecting mirror.

CONSTITUTION: The reflecting mirror 13 of the exposure lamp 14 is formed integrally with the base 3 made of light alloy extended between the 1st holding base 6 and the 2nd holding base 27. Pulleys 15 and 16 are provided rotatably near both ends of the vertical wall of the 3rd holding base 9 mounted slidably on a guide rail 4, and a wire 17 which drives both the 1st holding base 6 and the 3rd holding base 9 is extended. When a scanning motor 23 rotates clockwise, the holding base 6 moves to the right at a speed V accordingly and an original is scanned by exposure when the exposure lamp 14 is on. When this 1st holding base 6 moves to the right at the speed V and one pulley 16 mounted on the 3rd holding base 9 serves as a sliding pulley, so that the 3rd holding base 9 moves at a speed 1/2V in the same direction with the 1st holding base 6.