Hands-free phone-call device and tone quality control device

Constant phone-call quality is kept irrespective of setting of a tone adjusting function of a cellular phone under connection. There is provided a sound collector for collecting voices and converting the voices to a voice signal, a communication unit for communicating with a cellular phone terminal according to a predetermined communication protocol, and a reproducing unit for reproducing the voice signal received in the communication unit. A hands-free phone-call device for enabling the cellular phone terminal to execute hands-free phone call is provided with a signal processor for subjecting a voice signal to signal processing of adjusting tone quality to a predetermined state, and a controller for obtaining information on a tone adjusting function from the cellular phone terminal when the cellular phone terminal having the tone adjusting function for adjusting the tone quality during phone call is connected to communicate, and transmitting a predetermined command when it is determined that the tone adjusting function of the cellular phone terminal can be stopped or not, whereby the tone adjusting function of the cellular phone terminal is stopped and then the signal processor is made to execute the signal processing.