PURPOSE: To save and decode only a mail in an individual mail box for a specific user by saving a mail in the individual mail box into a secondary storage device and decoding the mail in the secondary storage device to the individual mail box.

CONSTITUTION: An electronic mail control program 1 receives an execution request (including information specifying a user) of mail save processing. The program 1 receiving the request publicates a start command of a mail save function 2 to a mail save decoding program 23. A function 2 requests the preparation of a secondary storage device 8 in use and the program 1 informs the request to the operator via a system console 7. The program 1 informs a preparation end command to the function 2 to open the secondary storage device 8 and outputs a head record representing data output start to the secondary storage device 8. A relevant individual mail box 40 is opened to read a mail and an end record is outputted to the secondary storage device 8 to terminate the mail save processing and the secondary storage device 8 is closed. A mail decoding function 3 reads a mail from the device 8 and writes it in a mail box 4.