An axial deviation of the sensor is corrected. An aiming device that calculates a correction parameter for correcting a detection result of a target sensor includes an estimated-track generation unit that detects a track of a target for a period when an own vehicle moves, by using information of a movement of the own vehicle, which is detected by a movement sensor, and generates a plurality of estimated tracks having different start-point positions from the detected track of the target by using a first variable group, a corrected-track generation unit that generates a plurality of corrected tracks from the track of the target around the own vehicle, which is detected by the target sensor, by using a second variable group, and a correction parameter calculation unit that selects a combination in which a difference between the estimated track and the corrected track is small, and calculates the correction parameter for correcting a displacement of the target sensor by using a first variable related to the selected estimated track and a second variable related to the selected corrected track.