A shared-use portable telephone has a ROM, RAM and control sections. The ROM section comprises a password area for holding passwords and a personal information area for holding personal information. The password and personal information areas include respective sub-areas that a plurality of users can utilize, respectively, based on their passwords. The control section copies the personal information stored in the personal information sub-areas to the RAM section that the users use in common and then to the personal information sub-area of the ROM section. The personal information sub-areas of the ROM section are used independently of each other, one for each user and never for any other user. Every time the portable telephone is used, the information stored in the RAM section is copied into the specific area of the ROM section. Each user can access his or her personal information, but cannot access the personal information of the other users.