Abstract: The present invention aims for improving convenience of management of information using blockchain or distributed ledger. A personal blockchain generation unit 51 of a service providing server group 1 generates or updates a unit file containing a history of transaction of data change related to a predetermined unit such as an account and a data for a plurality of users in an account management service of virtual currencies or medical information management service. A finality transaction file generating unit 52 generates a file containing a content of the transaction when the transaction in which the predetermined user is involved for each of the transaction related to the predetermined unit is finished. A management control unit 53 performs a control for storing the unit file independently from the other units and managing the unit file separately from the other units file for each of the units in a predetermined service. At this time, the unit file is managed as a block of a blockchain.