To surely identify the position and attitude of a camera with a high accuracy by providing means for raising the recognition ratio of markers on a position identifier.

A plurality of markers 8 provided on an object in advance are marked by a material which strongly reflects only a specified beam of X-, infrared, visible, ultraviolet rays, etc., and a camera 1 photographs the specified beam. When a marker recognizer 2 extracts the position of the marker seen on the image, it recognizes a part with much of specified light component as a marker 8, enabling a high recognition ratio. Using the positions 3 of a plurality of recognized markers 8 on the image and the absolute positions 5 of markers registered in advance, an attitude calculator 4 calculates and outputs the position and attitude of the camera. A camera position identifier 7 is constructed on a computer and involves the marker identifier 2, and the position and attitude 6 of the camera, and the marker 8 on the object can be surely recognized with a high accuracy by this method.