PURPOSE: To set the communication speed to the optimum speed automatically by inhibiting the communication at the communication speed when the number of times of errors stored in an error number storage means is prescribed number of times or above when the communication with a calling destination stored in a calling destination information storage means is applied.

CONSTITUTION: In the case of an abbreviation dial calling, a control section 3 reads the number of times of errors at the operating communication speed decided among the number of times of errors corresponding to an abbreviated number used for this call from a memory 10 and when the read error number of times is a prescribed value or above, the operating transmission speed is decreased by one rank. The operating communication speed being the highest among the communication speeds of an opposite terminal equipment and its own terminal equipment is decided except the communication speed whose error number of times is a prescribed value or above in such a manner.