Change of voice, especially hoarseness was regarded as a main symptom in laryngeal disease. Therefore, the voice evaluation should be objective, visible and quantitative. Parameters such as frequency, amplitude, maximal phonation time and mean air flow rate were used as quantitative data but they were not visible. Since the invention of sonagraph, it became possible to display voice quantitatively and visibly. Until 1970's, morphologic studies of voice using sonagraph were done and Yanagihara made a grading of hoarseness. In 1980, Imaizumi made quantitative parameters of voice and used them to differentiate laryngeal diseases. In this study, parameters were made from noise and high frequency components were used to explain Yanagihara's type objectively. Modification of Imaizumi's parameters extending their range beyond 2-3 kHz were made and practical use of them was tried. From 39 patients with hoarseness due to laryngeal disease and 39 normal persons, nine parameters were made using sonagraph. Thresholds of parameters differentiating normal voice from pathologic voice were derived from 6 parameters. To get normal range, the number of cases should be increased. The clinical application of these parameters for the evaluation of laryngeal disease should be tried in next study.