PURPOSE: To effectively take-in wind power and obtain strong power by enclosing rotatable one half of a vane wheel with a hood and constituting the hood so as to be revolved by the wind power received by a wind direction vane in the state where the other one half of the vane wheel faces directly against the wind.

CONSTITUTION: If a wind blows in the direction of arrow A in the figure, the direction vane 11 which is arranged on the hood 6 enclosing one half of a vane wheel 3 rotatable is set parallel to the direction of the wind and positioned on the lee, and the opening part 10 of the hood 6 is positioned perpendicularly to the wind direction, and the other one half of the vane wheel 3 faces directly against the wind direction. Accordingly, the wind A which dashed against wind vanes 5 revolves the vane wheel 3 in the direction B, and the wind A which dashed against the hood 6 flows in the direction of the wind direction vane 11 along the aucuate surface of the hood 6, and the vane wheel 3 receives wind power effectively and revolves most efficiently. When the direction of wind changes, the hood 6 turns so that the wind direction vane 11 is positioned on the lee, so that vane wheel 3 is revolved effectively even if wind blows in any direction.