An object of the invention is to greatly downsize the physical circuit size by achieving balance correction between the divided areas of an image sensing area by a digital signal process for A/D-converted digital data from a CCD. There is provided an image signal processing apparatus characterized by including an image sensing device which has an image sensing area divided into a plurality of areas, generates image signals in the divided areas, and outputs the image signals, a balance correction device which corrects the balance between the image signals of digital values from the divided areas, a synthesis device which synthesizes the image signals of the divided areas to generate one image data, and a defect correction device which corrects a defect of the image signal synthesized by the synthesis device.