An image correction apparatus, comprising: a line memory for a predetermined number of lines configured to store sequentially image data obtained by image pickup via an optical lens; a distortion correction value storage configured to store a distortion correction value, which is a predetermined value to be used in the correction of optical distortion occurring in the image data due to distortion aberration present in the optical lens; an image data control unit configured to select pixels of image data stored in the line memory as pixels to be corrected for the correction of optical distortion respectively, configured to determine a region for use in correction having a fixed number of pixels horizontally and a fixed number of lines vertically, the region containing a plurality of pixels for use in correction of the pixels to be corrected, based on the positions of the pixels to be corrected and the distortion correction value obtained from the distortion correction value storage, and configured to read out image data within the region for use in correction from the line memory; and a distortion correction unit configured to determine pixel values for the pixels to be corrected based on (i) the pixels for use in correction, which are contained in the image data, within the region for use in correction, read out by the image data control unit, and (ii) the distortion correction value, characterized in that: when the size of optical distortion occurring in the image data exceeds a maximum value of optical distortion where the optical distortion is correctable using image data obtained from the line memory of a predetermined number of lines, the image data control unit adjusts the distortion correction value obtained from the distortion correction value storage by multiplying the distortion correction value by a correction amount of correction value, which is a positive real number less than 1, in such a manner that the adjusted distortion correction value is less than or equal to a distortion correction value for correcting the maximum value of optical distortion using the image data obtained from the line memory. a line memory for a predetermined number of lines configured to store sequentially image data obtained by image pickup via an optical lens; a distortion correction value storage configured to store a distortion correction value, which is a predetermined value to be used in the correction of optical distortion occurring in the image data due to distortion aberration present in the optical lens; an image data control unit configured to select pixels of image data stored in the line memory as pixels to be corrected for the correction of optical distortion respectively, configured to determine a region for use in correction having a fixed number of pixels horizontally and a fixed number of lines vertically, the region containing a plurality of pixels for use in correction of the pixels to be corrected, based on the positions of the pixels to be corrected and the distortion correction value obtained from the distortion correction value storage, and configured to read out image data within the region for use in correction from the line memory; and a distortion correction unit configured to determine pixel values for the pixels to be corrected based on (i) the pixels for use in correction, which are contained in the image data, within the region for use in correction, read out by the image data control unit, and (ii) the distortion correction value, characterized in that: when the size of optical distortion occurring in the image data exceeds a maximum value of optical distortion where the optical distortion is correctable using image data obtained from the line memory of a predetermined number of lines, the image data control unit adjusts the distortion correction value obtained from the distortion correction value storage by multiplying the distortion correction value by a correction amount of correction value, which is a positive real number less than 1, in such a manner that the adjusted distortion correction value is less than or equal to a distortion correction value for correcting the maximum value of optical distortion using the image data obtained from the line memory.