1. An image display device for direct drawing apparatus for performing direct drawing of a predetermined pattern on a drawing object by scanning with a drawing beam, comprising: an acquisition part for acquiring design data in a vector format describing said pattern; a specified parameter setting part for setting a specified parameter to be used for RIP development of said design data; a processing area setting part for setting a processing area of said design data to be subjected to RIP development; a display RIP development part for performing RIP development of a portion of said design data, which corresponds to said processing area, by using said specified parameter, to thereby obtain a specified image; and a display part for visibly displaying said specified image, wherein said RIP development performed by said display RIP development part is a display RIP development in which the amount of processed data is smaller than that in drawing RIP development for said direct drawing.