To increase the hidden surface processing speed by dividing a screen into many pixel blocks, searching for a pixel block that is completely included in a silhouette, registering the silhouette and excluding an object having its all apexes included in the silhouette from the hidden surface processing objects.

A silhouette selection part 52 expresses the screen of a display part by means of the pixel blocks which are obtained by dividing the screen into (n×m) pieces. A silhouette storage area 53 stores the array type variables which are prepared for every pixel block. An occlusion deciding part 55 refers to the array type variables stored in the area 53 to decide the occlusion about each object that is transferred from a distant view selection part 54. According to the occlusion deciding result, the hidden surface processing is skipped across a distant view object that is completely hidden by its front object and the skipped object is transferred to the subsequent processing.