To properly perform a coordinate conversion by eliminating the need of operations based on actual measurements.

This coordinate conversion device comprises a calculation means 12 for obtaining the angular view field, depression angle, and a distance between the center of an image pickup tube and a virtual screen of a camera based on information on the height of a camera, information on the focus of the camera, information on the height of a virtual screen obtained when the virtual screen formed of an image displayed on the screen is assumed to be present in an actual space, and world coordination information on infinite point in the virtual screen and a first conversion means 13 for obtaining a world coordinate coping with a distance from the camera at an objective position and the height of the objective position based on the results by a calculation means 12 and the image coordinate of the objective position on the virtual screen from the center point of the image pickup tube by the camera.