To match records at the time of update from more than one terminal and inform of the completion of the update of the records only to other necessary terminals, which are performing update operation to the same record.

When terminals 11-15 update the same object record in a data base 28 in a computer 29, a terminal which meets specific conditions of the main key and update frequency of the record first updates the record preferentially, so that the record is matched. Further, information on the connected terminals and information on the updating terminal are stored in a storage means 25, and an informing means 21 informs of the object record is already updated by referring the stored information only to other necessary terminals.