This obstacle detection device is mounted on a vehicle. The obstacle detection device has a plurality of ultrasound sensors and a detection unit. The plurality of ultrasound sensors transmit a plurality of different frequencies of ultrasound onto overlapping detection areas and at overlapping transmission timings and receive returning ultrasound. The detection unit identifies what ultrasound from among the plurality of frequencies of ultrasound was reflected to produce the received returning ultrasound and detects the position of an obstacle in the vicinity of the vehicle.
