The behavior of condensate on a condensing surface is greatly affect by the heat transfer characteristic. Therefore, it is very important to make clear the shape of a stationary single droplet on a horizontal flat plate. We have reported the study on dropwise condensation. One of the authors investigated the heat transfer characteristic on a horizontal tube in dropwise condensation. In this paper, the shape of a single water droplet was observed by using a CCD camera. These experimental results were compared with its results of calculation based on an empirical formula. And using the maximum bubble pressure method the dependence of temperature on surface tension was investigated. Based on these results, it was found that the shape of a single droplet can be easily estimated and surface tension was influenced by variable temperature.