PURPOSE: To provide automatic adjustability for vanes of a fan-driven generator by installing vanes on spokes resiliently, adjusting the pitch angle of the vanes according to the wind strength, and thereby eliminating delay in controlling.

CONSTITUTION: Spokes 5, 5 are installed radially on the drive shaft 19 of a fan-driven generator. Vanes 4, 4 are fitted on these spokes 5, 5 rotatably using a mount ring. Resilient members, 1, 1 are installed between the spokes 5, 5 so as to give the vanes 4, 4 a torque in the direction of the wind. The vanes 5, 5 are so arranged as to move till the position where the resilient members 1, 1 balance in accordance with the wind strength, and the pitch angle of the vanes 5, 5 is adjusted automatically.