1. A virtual-space shift control apparatus, comprising: a display having a display area on which a virtual space image is displayed; a detecting element that optically detects a touch operation or a drag operation of a pointing device having a plurality of pointing elements, performed on the display; a viewpoint-position information generator that generates viewpoint position information of the virtual space image based on the optically detected touch or drag operation of the detecting element; and a three-dimensional image generator that generates data on the virtual space image seen from a viewpoint indicated by the viewpoint position information and outputting a three-dimensional virtual image to the display, said display simultaneously displaying a virtual plane formed of a two-dimensional view of said virtual image and said three-dimensional virtual image.