1. A virtual-space shift control apparatus comprising: a detecting element that detects a touch operation or a drag operation of a pointing device having a plurality of pointing elements, performed on a display screen; a viewpoint-position information generator that generates viewpoint position information of a virtual space image based on the 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 image to the display.