PURPOSE: To improve the graphic drawing performance when a polygon to be painted out or part of a figure to be painted out is rectangular by extracting a part which can be painted out at a high speed by hardware.

CONSTITUTION: The vertex data, order dot edge list, and active edge list of the polygon are arranged on a main storage 3. Then a drawing circuit 5 draws a graphic, corresponding to a drawing request received from a CPU 4, on an image memory 6. Thus, a rectangle painting-out function by hardware than a raster type bit map display device generally has is utilized so as to draw a drawing, where polygons including a special shape are painted out frequently, at a high speed. Consequently, the drawing speed when the polygon consists of rectangles partially or entirely is improved.