An image processing apparatus includes a binarization unit, a determination unit and a pixel value calculating unit. The binarization unit binarizes image data. The determination unit determines as to whether or not each pixel of the image data binarized by the binarization unit forms a peripheral portion of a pixel block. The pixel value calculating unit calculates a corrected pixel value of the pixel block based on (i) pixel values of pixels which are determined by the determination unit not to form the peripheral portion of the pixel block and (ii) pixel values of pixels forming the pixel block.