1. A system for processing simple X-ray images for diagnosing orthopedic diseases and diseases that are subject to oral surgery, the X-ray image processing system comprising: a computer; an X-ray image provision means for capturing simple two dimensional X-ray images as pixel data into the computer; means for carrying out a contrast adjustment process between a dark colored part and a bright colored part on a target X-ray image captured into the computer, wherein the pixel data of the X-ray image has a predetermined contrast, and a height is added to the two dimensional plane X-ray image; a light irradiation means for irradiating light to an outline area raised from an arbitrary angle so as to cause the area to be seemingly floated from the surface; an emboss-processing means for carrying out an embossing process on the contrast-adjustment processed X-ray image, by using an emboss filter to arithmetically convert gradation values in each of the pixel data of the target X-ray image to bring the image into a three-dimensional state; a shading means for adding light irradiated from a given angle and shade to the pixel data of the emboss-processed X-ray image, so that depth is added to height, thereby obtaining a visually three-dimensional floated image; image management means for storing and managing the emboss- and shading-processed X-ray image; and image output means, responsive to said image management means, for outputting the visually three-dimensional floated image on a display monitor or to a printer.