A video game apparatus includes a CPU, and the CPU executes a game according to a game program in a virtual space. During the game, the player selectively displays a 2D game screen and a 3D game screen by operating a controller. It should be noted that a player character, etc. is subjected to a modeling process in a virtual three-dimensional space, and the image is photographed by a virtual camera so as to be displayed as a 2D or 3D game screen on a monitor. If it is determined whether or not the player character and the predetermined object are contacted with each other, collision data for 2D display or collision data for 3D display set in advance to the object is utilized.