To automatically update respective application sets(ASs) so that a plurality of clients can operate using the newest versions to be owned by the clients themselves.

A server A is provided with a table F01 for managing the AS numbers of the newest ASs to be owned by a plurality of clients and a data base F02 storing data for updating the ASs of respective clients. At the time of receiving the information of a current AS number from a certain client, the server compares the received AS number with the current newest AS number, and when both numbers coincide with each other, transmits a station opening message indicating normality to the client. When both numbers are different from each other, the server transmits an updating instruction to the client. At the time of receiving an updating data transmission request from the client, the server transmits data for updating the current AS to the newest AS to be owned by the client to the client.