To provide a mobile telephone system which sends the electronic mail of a message which copes with a response disabled state from a call-out terminal to a call-in terminal, when a call-in terminal is kept in a state where it is unable to respond to the call-in.

When a portable telephone 15B is in a response unable state, in which a user is out and a telephone is set at recording, a telephone is out of service coverage, or a telephone is busy and unable to respond to the call from a portable telephone 15A, a message such as 'please call me back, when you return', 'please call me back, when you are located in a telephone coverage', or 'please call me back, when you are finished with telephoning' or in the other response unable state, a message such as 'this call cannot be completed' for a non-specific terminal or 'I cannot attend the meeting today' for a specific terminal is sent to a call-in terminal by electronic mail. The user of the portable telephone 15B ascertains the messages displayed on an LCD, and surely and quickly confirms call-in occurring in his response unable state. The user of the portable telephone 15B is capable of quickly starting communication with the call-out terminal for coping properly with a situation, after the return to a response able state.