In a positioning augmentation device (40), a plan making unit (84) selects a subset satisfying selection conditions from within a candidate set that is a set of satellites being selection candidates and saves plan data (43) indicating the selected subset in a memory (72). A plan alteration unit (85) acquires integrity information indicating quality of a positioning signal transmitted from each satellite and detects a satellite of which the quality of the positioning signal does not satisfy quality conditions, from within the subset selected by the plan making unit (84), based on the acquired integrity information. The plan alteration unit (85) replaces the detected satellite in the subset with another satellite included in the candidate set. A message generation unit (87) makes satellites, included in the subset indicated by the plan data (43) saved in the memory (72) among the satellites included in the candidate set, objects of positioning augmentation and generates a message (41) for distribution of augmentation information to be used for the positioning augmentation.