PURPOSE: To attain the transmission reception of an electronic mail through the use of an existing private telephone network by connecting an electronic mail communication terminal equipment able to be switched with a telephone set of the private telephone network.

CONSTITUTION: A display exclusive terminal equipment 3 is connected to a private telephone line 6 or a telephone set 5 and is a display exclusive set displaying a reception message, and the plural terminal equipment 3 are installed. Furthermore, a message input output terminal equipment 4 is installed for 7 or 8 sets of the telephone sets 5 and connected to the private telephone line 6 or the telephone set 5. That is, the display exclusive terminal equipment 3 or the message input output terminal equipment 4 as the electronic mail communication terminal equipment is connected to the telephone set 5 connecting to the private telephone line 6. The usual telephone function is obtained by connecting the private telephone line 6 to the telephone set 5 in this way and the electronic mail function is obtained by connecting the private telephone line 6 to the electronic mail communication terminal equipments 3, 4.