1. A moving-object position/attitude estimation apparatus for estimating a position and an attitude angle of a moving object, comprising: an image-capturing circuitry configured to acquire a captured image by capturing an image of surroundings of the moving object; a comparative image acquiring circuitry configured to acquire a comparative image viewed from a predetermined position at a predetermined attitude angle; a likelihood setting circuitry configured to compare the captured image acquired by the image-capturing circuitry with the comparative image acquired by the comparative image acquiring circuitry and set a higher position likelihood or a higher attitude angle likelihood as a number of pixels at which edges on an edge image calculated from the captured image are located at pixel coordinate positions of edges on the comparative image increases, and to assign a high attitude angle likelihood to the comparative image in a case where a distant-position pixel in the captured image matches a distant-position pixel in the comparative image and assign a high position likelihood to the comparative image in a case where a proximal-position pixel in the captured image matches a proximal-position pixel in the comparative image; and a moving-object position/attitude estimation circuitry configured to estimate the attitude angle of the moving object based on the attitude angle of the comparative image assigned the high attitude angle likelihood by the likelihood setting circuitry and estimate the position of the moving object based on the position of the comparative image assigned the high position likelihood by the likelihood setting circuitry.