An image processing device includes a retinex-value calculating portion, a normalizing-parameter reading portion, a normalizing portion, and a correcting portion. The retinex-value calculating portion calculates a retinex value of each pixel in an original image based both on a pixel value of a subject pixel and on a peripheral average luminance of the subject pixel, The normalizing-parameter reading portion reads an upper limit and a lower limit for performing normalization. The normalizing portion normalizes the retinex value based on the upper limit and the lower limit, thereby obtaining a normalized retinex value for each pixel in the original image. The correcting portion corrects the original image based both on the normalized retinex value and on the pixel value for each pixel in the original image, thereby obtaining a corrected image.