Abstract: An obstacle detection device includes: an ultrasonic sensor signal processing unit detecting at least a distance to an obstacle among the distance and a shape of the obstacle based on an output of an ultrasonic sensor, the ultrasonic sensor being disposed on a door of a vehicle and detecting the distance within a predetermined detection range by an ultrasonic wave; a camera image processing unit detecting the distance and the shape based on an output of a camera of the vehicle, the camera capturing an image of an area including a trajectory range when the door is opened and a detection range of the ultrasonic sensor; and a controller performing open operation control of the door based on detection results of the ultrasonic sensor signal processing unit and the camera image processing unit.