PURPOSE:To change the rotating speed of a wind direction changing plate to the high, medium, low speed or reverse by turning wind direction changing blades provided on the wind direction changing plate so as to change the rotating force applied to the wind direction changing blades by means of a forced air current by a fan. CONSTITUTION:When many wind direction changing blades provided on a wind direction changing plate 16 and pivoted rotatably on a central pivot axis (not shown in the diagram) are turned so that a state b7 is changed to a state b1, b2, b3, b4, or b8, a clockwise rotating force fa is applied to the wind direction changing blades 72, 72, a clockwise rotating force of 2fa is applied to the wind direction changing plate 16, and the rotating speed is increased (high speed). When the wind direction changing blades 72 are rotated into a state b6, a counter-clockwise rotating force fe is applied to the wind direction changing blades 72, a counter-clockwise rotating force of 2fe is applied to the wind direction changing plate 16, and the rotating speed is decreased (low speed). When said force 2fe exceeds a force for obtaining a preset optimum rotating speed (medium speed), the wind direction changing plate 16 is reversed.
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