A database system comprises a determining part 13 determining whether or not to conceal information to be registered in a database, a terminal device 1 that, if the determining part 13 determines that the information is to be concealed, generates N information fragments by secret-sharing the information and sends the N information fragments to a system management device 2, where N is a predetermined positive integer, the system management device 2 sending the N information fragments received from the terminal device 1 to N different database devices 3, and N database devices 3 each storing one of N information fragments received from the system management device 2.