An image processing device includes an image acquisition part acquiring first image data, a character detector detecting, based on the first image data, data of a character area in the first image data, a marking detector detecting, based on the first image data, data of a marking area in the first image data, an image adjustment area determination part determining, based on a detection result of the character detector and a detection result of the marking detector, data of an image adjustment area in the first image data, and an image processing part subjecting the data of the image adjustment area in the first image data to image processing to output second image data.