A three-dimensional simulator which can form a high quality image on a real time basis even when a large number of display objects gather in the vicinity of a visual point. An object image information memory section (212) stores a plurality of kinds of object image information including the number of different polygons (preciseness). First setting means (120) sets the preciseness in such a manner that the smaller the range of a serial number in which the serial numbers of display objects lie, the higher becomes the preciseness of the display objects. Second setting means (122) sets the preciseness in such a manner that the smaller the range of the distance in which the display objects are positioned, the higher becomes the preciseness of the display objects. The setting of the second setting means (122) is changed by the result of setting by the first setting means (120).