Abstract: The present invention includes: an identification code generation unit that generates, from information of a company code including a first code that uniquely identifies a management target in a part of a company in the part of the company and a second code that identifies the part of the company, an identification code including a history of the management target; a hash processing unit that hashes the identification code generated by the identification code generation unit according to a hash function and converts the hashed identification code into a meaningless code; and a reference code generation unit that generates a reference code unified for the entire company based on the meaningless code converted by the hash processing unit.