Recently various types of robots have being developed. The autonomous robot is enumerated as a kind of the robot which usually runs in structured environment. Thus the autonomous robot is not skillful in running on irregular terrains and automatic running by an autonomous robot on irregular terrains will enlarge negotiable environment for it. We have developed high maneuverability wheeled robot, HANZO, with variable structure functionality. In this paper, as the first stage of automatic running on irregular terrains, we realized the automatic step climbing up function for the robot.