Abstract: A roadside object detection apparatus to detect a roadside object using a plurality of captured images includes a height information detection unit configured to analyze the captured images, and to detect height information of an object in the captured images in a neighboring region having a distance less than or equal to a threshold from a vehicle having the roadside object detection apparatus installed; a height change detection unit configured to detect a change of a height of a road surface due to the roadside object from the height information in the neighboring region; a characteristic point extrapolation unit configured to determine positions having the change of the height detected as characteristic points of the roadside object, and to extrapolate the characteristic points into a far-off region having a distance greater than or equal to the threshold from the vehicle, based on a road model; and a roadside object detection unit configured to set a search range for the roadside object in the far-off re