A template image creation module generates in predetermined timing a template image corresponding to a landmark existing in a real space from a fixed viewpoint image obtained from a fixed camera, and provides the template image to a landmark detection module, thereby updating a template image for use in template matching. The landmark detection module performs template matching for a photographed image from an observer viewpoint camera that is mounted on a HMD and moves along with an observer, using the template image updated by the template image creation module to detect the position of the landmark in the photographed image. In this way, specific points can be reliably detected from a photographed image, even if the environment during picture-taking is changed to cause changes in how specific points are viewed.