To dissolve inconvenience owing to a caller number informing service by resetting a telephone number used at the time and performing a call again in the case that a busy tone is detected immediately after an opposite terminal responds and a line is disconnected.

A destination telephone number operated and inputted by a user is inputted and stored in a system memory 2. A system control part 1 reads the stored telephone number, connects the line by performing off-hook and starts the detection of polarity inversion. Then, the dial signals of the read telephone number are successively sent out and signals CNG are sent out corresponding to a group 3 facsimile transmission means. Before the prescribed time elapses after the signals CNG are sent out, in the case of detecting the polarity inversion and in the case that the busy tone is detected and the line is disconnected, it is judged that a 'telephone number informing request function' is set on an opposite terminal side, the telephone number stored in the system memory 2 is changed to the value of a telephone number informing state and the opposite terminal is called again by using the changed telephone number.