1. A detection device comprising: an image acquisition section that acquires an image that has been captured by an imaging section, and includes an image of an object; a distance information acquisition section that acquires distance information based on a distance from the imaging section to the object when the imaging section captured the image; a feature quantity calculation section that calculates a feature quantity relating to the object from the acquired image; a learning feature quantity storage section that stores a learning feature quantity that has been calculated by a learning process corresponding to each of a plurality of distance ranges and corresponds to each of the plurality of distance ranges, the plurality of distance ranges being set corresponding to the distance from the imaging section to the object; and a detection section that detects a target area from the image based on the learning feature quantity, the distance information, and the feature quantity, the detection section determining a distance range that corresponds to the feature quantity calculated by the feature quantity calculation section from the plurality of distance ranges based on the distance information acquired by the distance information acquisition section, and detecting the target area based on the learning feature quantity that corresponds to the determined distance range, and the feature quantity calculated by the feature quantity calculation section.