PURPOSE: To stably read an original by installing an, butting member for sandwiching a guide member and an energizing body for pressing the abutting member on a traveling body.

CONSTITUTION: As to the traveling bodies 45 and 47 for 1st and 2nd mirror bases 41 and 42, the 1st and 2nd mirror bases 41 and 42 are pressed in the direction of the guide member 43 positioned on the front side by the abutting member 56 which is pressed against the inclined surface 50 of the guide member 43 by the energizing body 57, and also, the abutting member 51 of the traveling bodies 45 and 47 is pressed against the horizontal surface 49 of the guide member 43. As to the traveling bodies 44 and 46 positioned on the front side of the 1st and 2nd mirror bases 41 and 42, the inclined surface 50 is pressed forward by the abutting member 52. Then, on the front side of the 1st and 2nd mirror bases 41 and 42, the abutting member 51 of the traveling bodies 44 and 46 is pressed against the horizontal surface 49 of the guide member 43. Thus, in the case of scanning the original, the 1st and 2nd mirror bases 41 and 42 can be stably moved back and forth with hardly vibrated back and forth.