PURPOSE: To quicken the setting of an original and to attain high accuracy by projecting inversely a linear light onto an original table via an input optical system corresponding to the length of an effective picture element region of a CCD line sensor and moving the projection image.

CONSTITUTION: A linear light source 13 comprising a rod halogen lamp 11 and a slit 12 of the same length as the effective picture element region of a CCD line sensor 7 is provided on an optical path branched by a half mirror 10 at a position symmetrical to the CCD line sensor 7 with respect to an original 2. Moreover, a projecting image moving mechanism moving an original table 1 and a projection image 14 of the linear light source 13 with respect to the original table 1 relatively in a direction (subscanning direction) orthogonal to the projection image 14 is provided. Thus, the original is set sufficiently quickly with high accuracy within the picture read effective region on the original table 1.