A technique of estimating, based on a camera image captured from a mobile object, the position coordinates of an ambient object or the mobile object itself is offered. A plurality of camera images that are captured at different geographical locations and contain at least one identical stationary object are acquired; position coordinates of the imaging locations of the corresponding camera images are acquired; and the position coordinates of the stationary object are estimated based on the position coordinates of the imaging locations and gaze vectors oriented from a camera to the stationary object in each of the camera images. Alternatively, a camera image that contains at least two stationary objects having position coordinates that are known is acquired; and the position coordinates of a location at which the camera image is captured are estimated based on the position coordinates of each of the stationary objects and a gaze vector oriented from the camera to each of the stationary objects in the camera image.