1. A non-transitory computer-readable storage medium having stored therein an information processing program to be executed by a computer of an information processing apparatus which displays a stereoscopically visible image of a virtual three-dimensional space taken by a virtual stereo camera, on a display apparatus capable of displaying a stereoscopically visible image, the information processing program causing the computer to perform functions and operations comprising: setting a position of a virtual preferential display object, which is a specified three-dimensional virtual object, within an imaging range of the virtual Stereo camera in the virtual three-dimensional space; taking an image of the virtual three-dimensional space using the virtual stereo camera, and rendering a stereoscopically visible image of the virtual three-dimensional space; and causing the display apparatus to display the stereoscopically visible image; wherein the virtual preferential display object is rendered stereoscopically visible and displayed within the stereoscopically visible image by applying a parallax value associated with a first depth from the virtual camera in accordance with a preference order for displaying virtual objects which is determined from a second depth which is shallower than the first depth from the virtual stereo camera, and wherein a virtual three-dimensional object placed at an intermediate depth between the first depth and the second depth in the virtual three-dimensional space is caused to be displayed based on a relative preference order depending on the intermediate depth and a parallax represented by the intermediate depth, except that the virtual preferential display object is rendered in preference to the virtual three-dimensional object placed at the intermediate depth.