An object detection device includes: an ultrasonic sensor for transmitting a signal and further receiving reflected signals of the transmitted signal; a delay-sum processing unit for generating two-dimensional distance information in which the reflected signals received by the ultrasonic sensor are delay-summed in a plurality of reference planes set in advance; a distance information integration unit for generating integrated distance information in which the two-dimensional distance information in the plurality of reference planes generated by the delay-sum processing unit is summed in a vertical direction to the reference planes; and an object detection unit for detecting an object at a position where an intensity in the vertical direction is equal to or larger than a threshold value by referring to an intensity in the vertical direction of the integrated distance information generated by the distance information integration unit.