AUTONOMOUS TRAVEL DEVICE AND AUTONOMOUS TRAVEL METHOD, AND PROGRAM THEREOF

PROBLEM TO BE SOLVED: To provide an autonomous travel device capable of traveling autonomously without using guide lines such as white lines even in a road having a branch.SOLUTION: An autonomous travel device detects respective height of grids virtually provided on a contact surface within a detection area in the periphery, and detects grids having a difference in height more than a road shoulder detecting reference value compared with neighboring grids, as grids showing road shoulder points. Then, road shoulder lines on both of right and left sides are identified by connecting the road shoulder points on each side detected on the respective right and left sides of a reference path within the detection area, and the shape of the road is recognized on the basis of each of the road shoulder lines on both of the right and left sides. Besides, the grids are identified shown by a plurality of path candidates virtually provided between the road shoulder lines on both of the right and left sides within the detection area, and a path candidate having small variation between the height of grids shown by the path candidate and that of other grids adjacent to the grids shown by the path candidate is identified as a travel route.