Researches on free-falling water droplet have been conducted in a long time. However, there are few numerical analyses closing to realistic free-falling phenomenon. In this study, We developed a two-phase flow analyses program based on CCUP method and Level Set method applied by RCIP method. And the numerical analyses of free-falling water droplet in the air were carried out. The droplet diameter is 1mm and 1.6mm. As a result, the falling velocity of two water droplets were close to values based on the experiment. In addition, it is found 1mm water droplet shows spiraling trajectory, which was not shown for 1.6mm droplet water. The spiraling trajectory is related to the vortex existing near droplet surface and moving around the surface.