The invention is to provide a light-focusing for image-gathering device that receive the light coming from the image of an object being scanned. The light-focusing for image-gathering device is comprised of: at least one reflection mirror, an imaging device and at least one raster (optical grate). The reflection mirror has plural concave surfaces that are arranged appropriately, and the concave surface provides the light being focused and reflected to a predetermined route. The imaging device receives the light reflected from at least one reflection mirror and converts it into electronic signal. The raster has plural pervious holes, of which positions are just respectively corresponded to each concave surface. The raster is located in the light-path route between the imaging device and at least one reflection mirror. When an image data of an object being scanned that can be divided into receivable image-and-light signal of the object being scanned and un-receivable image-and-light signal of the object being scanned is gathered executively, the un-receivable image-and-light signals of the object being scanned are first removed, then the adjacent receivable image-and-light signal of the object being be scanned is connected together to obtain a complete image output data.