In the world, approximately 800 million people have difficulty in use of hygienic water. It is necessary to use the water of non-hygienic well water, pond, and river in the country which is not maintained of water service facilities. Because a water purifier and the water conversion device are expensive, and stable electricity and high technology are necessary, anyone is not a thing usable anywhere. Therefore, the use of the solar heat water conversion device is the appropriate solution in these countries. It is a reason to be a method to secure the drinking water which it is low cost, a low technique, electricity-free, and is safe. In this study, the characteristics of the water generation in the solar heat water conversion device （TSS: Tubular Solar Still） made clear by outdoor experiments in Hiroshima, Japan and indoor experiments. Basic knowledge of the relation between the production of water generation and the initial depth of the water and the reflection rate of the ground surface in the device is got in this study.