1. An image reading apparatus to read an image of document, comprising: a storing section for storing image data obtained by reading area lager than said document; an outline information extracting section for extracting outline information of said document according to the image data stored in said storing section; and a compounded-image outputting section for forming outline image of said document according to the outline information extracted by said outline information extracting section, compounding the outline image with said image data, and outputting the compounded image.