To provide a mobile telephone terminal which is capable of mitigating burden on the user when telephone directory information is backed-up and reducing likelihood of erasure of the telephone directory information. If a user newly registers a telephone number list or changes or deletes the telephone number list stored in a telephone directory storage unit by actuating a key entry unit when telephone directory update notification mail transmission preset flag and automatic transmission preset flag are in the on-states, a control unit automatically transmits a telephone directory update notification mail in which update contents of the telephone directory information are described to a mail address which is stored in a transmission destination mail address area.