In this paper, an attempt has been made to show the important rôle of negative vortioity, that was introduced through theoretical considerations, by the analysis of actual data obtained of the typhoons “Kitty” and “Jane”. The fine structure of a tyhoon, that some small vortical cells of about 50_??_100km in diameter and of signs of vortioity + and - are embedded in a large vortex, was elucidated by the following observational facts: the distributions of wind velocity and of horizontal convergence and divergence, the intensity of rainfall and the changes of pressure distribution with time. The schematic diagram of the vertical cross section of a typhoon is set forth, based on these new observational features. In addition to these problems, the oscillation of a vortical cell in a typhoon is discussed.