Abstract: A rotating wind-guiding shell for an electrical fan effectively changes the direction and magnitude of the blowing wind from the fan. The pressure and the direction of the wind from the fan can be varied instantaneously and the effective wind field can also be enlarged. At any place within the effective wind field, one can produce a variation of the pressure and the direction of the wind from the fan while it is continuously operating. The structure of the device is simple so that its cost is very low and it can be used as a desk-fan, floor-fan, ceiling-fan or a wall-fan by a simple adjustment at its support.