PURPOSE: To obtain a proper image signal regardless of the size of the difference of luminance between a bright area and a dark area.

CONSTITUTION: Objectives are respectively image picked-up with the different exposure of the ratio 5:1 by CCD 14 and 15. When the luminance peak value of a video signal outputted from CCD 15 is over the 40% of a white level (namely, when the luminance of the bright area is over the twice of that of the dark area), the montage synthesizing of the image is selected and when the peak value is less than 40%, knee processing is selected. At the time of montage synthetic processing, the video signal in the relatively bright area of the image expresses with the video signal obtained from CCD 14 is replaced by the video signal in the area corresponding to the image expressed with the video signal obtained from CCD 15 (multiplexer 28). At the time of knee processing, the high luminance area of the output video signal of CCD 14 is luminance-level-compressed (white level compression preknee circuit 18).