The concentration of total sulfur and sulfurous odrants in the water and silt, which were picked at the Lake Biwa and Ohi River, were examined by applying G C method and T-S monitor. Following results were obtained. 1. H2S and DMS were detected in all samples of bottom water, and over 80% of the detected sulfurous concentration were occupied by the sum of these two components. And also, DMDS and MeM were detected in many samples of bottom water. 2. The relation between total sulfur concentration in the silt and in bottom water was not clear, but it was suggested that the ratio of sulfurous odorants to total sulfur components in water was nearly constant. 3. The volume of evaporated sulfurous gases was considerably varied with the location where samples were taken. The values of μg-H2S/g-dry mud at 20°C were obtained as 8 to for the Lake Biwa, 110 for Seta River and 12 to 165 for Ohi River. 4. It was confirmed that the total sulfur monitor (FPI) type or coulometrie type) was very available for the continuous measurement of evaporated sulfurous components.