Assume that the memory card 203 is mounted in advance on an external interface 67. [0211] With this being presumed, when the hand held telephone set 401 is powered ON at the step F1 of the flowchart shown in FIG. 16, a main screen is displayed on a liquid crystal display monitor 122 at the step F2. [0212] Then, at the step F3, whether or not there is a message such as E-mail is displayed on the li