When a player character is moved toward a two-dimensional non-player character (NPC) in response to operation of an input section 21 by a player, a main process is repeatedly carried out by a video game apparatus 100. Thus, the two-dimensional NPC approaches the player character and is moved toward a visual boundary surface, and finally leaves the field of view of the virtual camera without moving within the 2D inhibit space. Because the two-dimensional NPC is maintained in a space opposite from the player character with respect to a boundary surface between 2D and 3D in this way, and the two-dimensional NPC is prevented from moving within the side of the player character P from the boundary surface between 2D and 3D, it is possible to reduce processing load of hardware without losing realism (realistic sensation) when an image including multiple objects is drawn in a virtual three-dimensional space.