To allow a user to simply confirm a mail and a message not only in voice but also with characters at a visiting place without the use of any other medium such as a portable telephone set or a PDE, to allow the user to simply transfer or reply to the mail or the message, and to store mail contents, a telephone number and a memory address number in a telephone-use IC card.

Information is read from a public telephone use-IC card 201 for storing an ID number, and when the information includes a mail or a message addressed to the ID number, it is served. Or, in the case of making a replay to or transferring the mail, a telephone number and a mail address are read from the IC card 201 so as to send the mail. In the case of entering characters, a voice conversion program 217 is used to attain character entry in voice. Moreover, mail contents, a message, a telephone number and a mail address are stored in the IC card 201.