Studies on analysis of voice have been for many years in various ways. In the mid-nineteenth century voice analysis was rapidly developed and investigated by famous acousticians like Helmholtz. However, it was not until some decades ago in Europe, the United States and Japan that electronic analysis of physical characteristics of voice were begun. Thus, internationally, there has been much scientific research in this field, but in Korea it still remained unexplored and has not captured the interesting of researchers. Since about 1943, Potter and others at the Bell Telephone Laboratories have studied sound spectrography. They published their research work, Visible Speech, in 1947, there by making a great contribution to the study of voice. They added information regarding objective observation of the physical nature of voice and made detailed observation easier by making it possible to obtain a three-dimensional record of frequency, intensity, and time relationship. I present this paper of research experience on the physico-acoustic analysis of vowels and consonants of normal male by using of the sonagraph at the Dept. of E.N.T. in Osaka city university, Faculty of Medicine, Research Institute of Logopedics and Phoniatrics, University of Tokyo, Faculty of Medicine, Institution for Phonetic Sciences, University of Kyoto, Faculty of Medicine and Dept. of E.N.T., Gurume University, Faculty of Medicine, Japan.