Information linkage system and information management method

It is provided an information linkage system, which is configured to allow a plurality of organizations to register and update data, and is formed of a computer including: a calculation device configured to execute predetermined calculation processing, to thereby implement the following functional modules; and a storage device accessible to the calculation device, the information linkage system comprising: an information linkage control module configured to receive a registration request for data, an update request for data, and an acquisition request for data from a plurality of external systems; an information linkage database in which data is allowed to be registered and updated; an information linkage database access module configured to access the information linkage database in response to a request received by the information linkage control module; and a reliability calculation module configured to calculate reliability information relating to the data stored in the information linkage database.