An actual-past-radiography position database stores, as actual-past-radiography positions, the position of a radiographic image detector and the position of a radiation source when radiography was actually performed, associating the position of the radiographic image detector and the position of the radiation source with information about a subject. When the radiation source and the radiographic image detector are positioned to perform radiography, position adjustment amounts for adjusting the positions of the radiation source and the radiographic image detector from standard positions stored in the standard position database are output, as aid information. The aid information is output based on the actual-past-radiography positions that are stored in the actual-past-radiography position database and that are associated with the information about the subject.