To cover a wide visual field by small number of ultrasonic sensors, and to realize shortening of a time interval of obstacle detection in a mobile machine provided with an ultrasonic sensor.
The mobile machine is provided with the ultrasonic wave sensor 2 having a transmitting element 21, and a plurality of receiving elements 31 arranged linearly or in two dimensions at a predetermined wavelength interval or less receiving an ultrasonic wave transmitted from the transmitting element 21 and reflected by an ultrasonic wave reflecting object 22, and a travel control means for traveling to autonomously move. An obstacle detecting means 35 intermittently carries out transmission by the transmitting element, and receiving by the receiving element to determine a distance and a direction to the ultrasonic wave reflecting object 22, and it detects an obstacle by using images created by a distance image creating means 36, a two-dimensional image creating means 37, and a detection image creating means 38. The mobile machine autonomously moves while avoiding collision with the obstacle on the basis of a detection result.
SAWADA KAZUO
YAMANAKA HIROSHI
