To provide a wind power generating device increasing electric power supply quantity by using a high capacity high output secondary battery.

An AC generator 2 is connected to a shaft of a wind turbine blade 1. The secondary buttery 4 is connected to the AC generator 2 via an AC-DC converter 3. A load 6 is connected to the secondary battery 4 via the AC-DC converter 5. Consequently, output generated by the wind turbine blade 1 rotating at high speed is not directly applied to the load 6, but all of the output is stored in the secondary battery once and then electricity is supplied to the load 6 from the secondary battery 4.