On a view point of a human-machine interface, the vocal sound is an effective medium of communication between human beings and machines both sides. Mechanism of phonation for living being is much complicated. Human phonetic organs consist of the lungs, the vocal cords, and the vocal tract. The phonemic characteristics of the vowels are determined by the frequency of the vocal cords producing fundamental sound and by the resonant behavior of the vocal tract modifying the sound to a voice. The purpose of this study is to make a human-like robot that utters sounds by a mechanical phonetic organ instead of an ordinary electrical approach. Vocal cords and a vocal tract model for mechanism of human-like phonation has been developed and Japanese five articulated vowels have been experimentally investigated by the developed resonant part.