To provide a voice processing apparatus for enabling a user to correctly listen to the voice transmitted from a portable telephone of the opposite party even at such a place where ambient noise changes rapidly.

A microphone 30 collects the user's voice of the portable telephone 2 and the ambient noise of the portable telephone 2 and outputs the user's voice and the ambient noise to an A/D converter 15 as an analog signal. A noise detecting part 5 detects only the intensity of a noise signal from a digital signal outputted from via the A/D converter 15. The portable telephone 2 outputs a voice analog signal transmitted from the portable telephone of the opposite party to an A/D converter 20. A speech communication voice quality control part 10 converts the intensity of the digital signal outputted from via the A/D converter 20 into the intensity equal to or greater than the intensity of the noise signal detected by the noise detecting part 5 to output the intensity to a D/A converter 25. A loudspeaker 35 outputs the voice of the opposite party of the portable telephone 2.