A power source is turned on by pressing a power source button in a key input part. Then, a telephone number is inputted from the ten keys in the key input part so that the telephone number is stored in a telephone number temporary memory part. After pressing a communication button in the key input part, conversation is held with the counterpart. Then, a finish button is pressed for finishing the communication. When it is finished, a list of telephone directories is displayed on a display device. In the case the input from the ten keys is the number information, the telephone directory for registration is selected from the "telephone directories 1 to 4" with different functions such that if the input is the number "1", the telephone directory 1" is selected, and if it is the number "2", the telephone directory 2" is selected. Furthermore, in the case of adding the name information to the telephone number, registration is executed in the selected telephone directory with the name information.