To eliminate a need of restrictions on input of transactions related to an investment and to effectively prevent mis-input due to manual input.

When plural agricultural cooperative associations are amalgamated, an investment balance account acquisition means 1 acquires all investment balances amalgamation object agricultural cooperative associations stored in a balance management DB 3 by retrieval, and an account shift data generation means 4 automatically generates account shift data 4 for update based on these acquired investment balances so that an already existing daily account system 5 which actually updates accounts can be used as it is to update the balance management DB 3 and an overall account ledger DB 6.