PURPOSE: To eliminate the influence of an error of a terrestrial magnetism sensor and to keep the parallelism of traveling loci of a running vehicle with high accuracy by controlling the following turning and straight traveling of the vehicle on the basis of the output of the sensor that is stored when the first turning of the vehicle is completed.

CONSTITUTION: An autonomously running vehicle, e.g. a lawn mower vehicle detects its traveling azimuth by a terrestrial magnetism sensor 3 and has the reciprocative traveling with turning. The traveling control part 23 of a controller 20 of the vehicle refers to the map of a work data accumulation part 24 to calculate an error between the present position and the target position of the vehicle based on the information received from a presumed dead reckoning position detection part 21. Then the part 23 decides a traveling path instruction, etc., to correct the error and evades the obstacles if detected or stops the vehicle. In regard of the autonomous traveling control of the part 23, the vehicle is turned based on the rotational difference between the right and left wheels when the vehicle body is first turned by 180° in a prescribed work area. The azimuth data on the sensor 3 is stored as the reference value when the turning of the vehicle is completed. Then the second and following turning and straight traveling of the vehicle are controlled, so that the vehicle body is set parallel to the azimuth of the sensor 3.