1. An image processing device which provides a detection result of additional information added to each of one or more pages which constitute a document, comprising: an input part configured to input image data of each page of a document; a detection part configured to generate a page detection result of additional information added to the image data, the page detection result being generated on a page basis and indicating a result of detection of the additional information for each page; and a detection result output part configured to output an outline result indicating an outline of the page detection results for the respective pages on a document basis, together with an identifier of the document associated with the outline result, wherein, when the page detection results of one or more pages of a document indicate that additional information is not added or additional information cannot be extracted, the detection result output part outputs an outline result of the one or more pages indicating that an irregular additional information is detected.