In the present invention, a
server calculates, for each tire, a remaining durability amount of the tires from the use history of the tires. If identification information of a tire is received, the
server determines
retread specifications for the case when the tire represented by the identification information is set as a tire casing, the determination made by using the remaining durability amount of the tire represented by the identification information. The
server then outputs the determined
retread specifications.