The obstacle detection for the vicinity of a central part of a driving lane are performed for fixed period through the ultrasonic object detection sections CNL and CNR.
An object detection device of the present invention is used to restrain deviations in obstacle detections by using a plurality of ultrasonic object detection sections. When four ultrasonic object detection sections (CRL, CNL, CNR, CRR) which are disposed at approximately equal intervals are driven so as to cover a whole lengthwise-direction region of a fender-guard section (11), the ultrasonic object detection sections are driven in an order from a left-end or a right-end, for example, from the left-end ultrasonic object detection section to the central section, and then from the right-end ultrasonic object detection section to the central section, i.e., the ultrasonic object detection sections are driven in the order of CRL, CNL, CNR, CRR. The ultrasonic object detection sections CNL and CNR are secondly driven after the left-end and the right end sections are driven, and thus the obstacle detection for the vicinity of a central part of a driving lane are performed for fixed period through the ultrasonic object detection sections CNL and CNR.