To modulate inputted voices to voices of various forms.

This voice modulator includes a codec for conversion of analog and digital signals, a CPU for carrying out operation for echo modulation, helium modulation and m modulation and a power source. In the helium modulation and the m modulation, a step of compensating the segments changed in length by compression or extension of the voice samples is provided. In the echo modulation, a step of applying a suitable factor to the voice sample generated before the specified time from the present voice sample, then adding the same to the present voice sample is provided. Such voice modulation system can be embodied in one chip by using an integrated circuit or can be embodied by a program applicable to a computer. More particularly when the method is embodied in the computer, a head set which connects voice modulating means and a cellular phone is provided in such a manner that a telephone call by vices can be made by connecting the means to the cellular phone.