1. An image pickup apparatus comprising: an image pickup device including a plurality of imaging planes each having different dark current characteristics, each of the imaging planes having an effective image area, that acquires image data and has horizontal lines, and an optical black (OPB) area that has horizontal lines corresponding to the horizontal lines of the effective image area; a memory that stores a dark current data table including difference data between dark current values pre-measured at upper and lower areas of the effective image area of each of the imaging planes and dark current values pre-measured at corresponding upper and lower areas of the OPB area of each of the imaging planes; and an image processing unit to receive a signal from the image pickup device and performing an image generating process, wherein the image processing unit calculates estimate dark current values for the effective image area of each of the imaging planes based on the dark current data table stored in the memory and actual dark current values measured in the OPB area for each of the imaging planes, and performs a dark current eliminating process on the basis of the estimate dark current values.