An object-detecting device includes a first detector, an object tracker, a second detector, and an axial misalignment determiner. The first detector detects a distance between a moving body and an object and an orientation of the object relative to the moving body based on detection information acquired from detection sensors including a search wave sensor that searches a detection region with a search wave. The object tracker tracks the same object passing through a different detection region based on the detection information. The second detector detects at least either one of a height of the object or a lateral distance of the object as object information based on the detection information. The axial misalignment determiner determines whether axial misalignment has occurred in the search wave sensor based on the distance and the orientation of the object detected by the first detector based on the detection information from the search wave sensor and the object information detected in a different detection region by the second detector.