On a radar apparatus, a direction derivation part derives a peak angle related to an angle of a target based on reception signals received by a plurality of reception antennas. Then, a detection information derivation part derives, based on the peak angle, target data that are internal data about the target, and stores the derived target data into a memory. A reliability determination part determines a reliability of an object peak angle upon which the target data about the target was derived, the reliability of the object peak angle being determined based on a different peak angle derived concurrently with the object peak angle by the direction derivation part. Then, a data erasure part deletes, based on the reliability of the object peak angle determined by the reliability determination part, the target data relevant to the object peak angle from the memory to exclude the target data from further processing.