1. An autonomous warehouse carrier which automatically travels on a pathway, comprising: an autonomous warehouse carrier main body which travels on the pathway including a first area and a second area other than the first area, the first area including a rack having provided thereon a reflecting plate and the rack provided along the pathway, and the second area including a wall provided along the pathway; a distance measuring sensor which is provided in the autonomous warehouse carrier main body, measures an intensity of reflected light a plurality of times, the reflected light being reflected from at least the reflecting plate, and obtains a plurality of pieces of measured data; a map data storage unit which stores map data in which structures provided along the pathway are recorded; an approximate line calculation unit which calculates an approximate line in the first area based on a set of pieces of measured data having the light intensity equal to or more than a predetermined threshold among the plurality of pieces of measured data in the first area and calculates an approximate line in the second area based on the plurality of pieces of measured data in the second area; and a position calculation unit which calculates a position of the autonomous warehouse carrier main body by collating the approximate line in the first area and the map data or the approximate line in the second area and the map data.