PURPOSE: To obtain a uniform picture signal by applying level correction to an analog picture signal from a CCD image sensor and synthesizing the result with a synchronizing signal.

CONSTITUTION: The output signal from the CCD image sensor 1 is fed to an AD converter 5 or a division circuit 10 via an amlifier 3 and a changeover switch. While the white background of the head of an original is read, a switch 4 is thrown in the position of 4-2 and the pattern of the white background is written in a 1-line memory 6. When the head of the original is passed, the switch is thrown to the position of 4-3, and a signal VA representing an original image is fed to the division circuit 10 one by one line. The division circuit 10 uses the signal VB corresponding to the pattern of the white part so as to divide the signal VA and the result is fed to a synthesis circuit 12. Then the synchronizing signal SYNC is inserted at the pause period of the image sensor 1 and outputted. Thus, the ununiformity of the image due to shortage of illuminance at the edge of the original is prevented.