The present system for automatically adjusting deposit balance is the effective measure for pay-off which calculates the excess amount by subtracting from the balance of the account established in one financial institution, the specified balance for the account and calculates the allowable amount by subtracting from the specified balance for the account established in other financial institution, the balance of the account and compares said excess amount with said allowable amount and sets the transfer amounts as the one lesser of either said excess amount or said allowable amount. Specifically the system for automatically adjusting deposit sets in addition the plus specified balance for checking and savings accounts and time deposit account respectively when said accounts include checking account and savings account and time deposit accounts. The system for automatically adjusting deposit further sets the minus specified balance for the debt amount. Preferably the system for automatically adjusting deposit is an apparatus which enables to maintain the necessary balance and calculates the deficit amount by subtracting from the balance for the account established in one financial institution, the necessary balance for the account and calculates the surplus amount by subtracting from the necessary balance for the account established in said other financial institution, the balance for the account and compares said deficit amount with the surplus amount and sets the amount that is lesser of said deficit or surplus amounts for the transfer amount.