The distribution of the pressure at any level depends not only on the distribution of the pressure but also on the distribution of temperature at the surface of the earth, as was shown by Margules, Shaw, Ryd, Brunt and Arakawa. Since the gradient of the surface pressure field decreases and the gradient of the surface temperature field increases with height, the wind due to the former will gradually be effaced, but the wind due to the latter will become more and more stronger with the increase of height. Thus, if the temperature gradient is very small and the height of typhoon is comparatively low, the movement of it will be controlled by the general current caused by the pressure gradient (see Fig. I). The consideration that a typhoon in a low latitude moves in the direction of the geostrophic wind and the velocity of it is proportional to the wind-velocity when the temperature gradient is negligibly small, was ascert_??_ined by Dr. Horiguti. On the other hand, however, if the temperature gradient is effective than the pressure gradient and height of typhoon is comparatively high the typhoon moves in the direction of isothermal lines and the velocity of it is proportional to the temperature gradient (see Fig. 2). In this paper, it is shown that the law hold good for four severe typhoons passed over the neighbourhoods of Japan Proper.