It is very important to find a new way of soil sterilization because the use of methyl bromide, which had been widely used all over the world, was banned in 2005 in Japan and will be in the world in 2010. Using hot water for soil sterilization has become popular in Japan as an alternative for methyl bromide. However, because using hot water is relatively new, few studies have been done. In this study, we investigated the dynamics of hot water in soil. Hot water with the temperature of 94°C was applied to the soil surface at the rate of 200L/m² during an experiment. A plastic film was used to cover the soil surface for decreasing heat loss from the ground to the air. The experiment was conducted in a greenhouse. Thermo-couples were used for measuring soil temperature, and time domain reflectometry was for water content. Soil temperatures were measured at 20cm, 30cm, 40cm, and 50cm deep, and water contents were measured between the thermo-couples, 20-30cm, 30-40cm, and 40-50cm deep. As the result of this study, water content increased steeply at every depth measured. It took 2 h that water moved down from the surface to the 50cm depth. In contrast, temperature rose more slowly. At the 50cm depth, temperature started rising approximately after 20h. Temperatures at the all measuring points had never reached over 55°C. Heat movement took more time than did water movement. Even after water movement stopped, soil temperatures increased until temperature was equilibrated. As most bacteria are dead at > 55°C, soil temperature rise in the root zone was not enough in this study.