PURPOSE: To effectively utilize the wind speed energy by generating the wave motion by allowing wind to pass through a rotatable type opening/closing device and permitting the power generation by the wave motion and allowing the meeting with the wind speed in the wide range ranging from weak wind to strong wind and permitting the following to the variation of the wind speed.

CONSTITUTION: Inside a case body 4 which can turn, following the direction of wind, a duct 8 having a wind collecting hood 9 and a wind discharging hood 6 at the both opened port edges is installed. A rotatable opening/closing device having a rotatable shutter 15 which is revolved by a propeller 14 revolved by wind is installed in the wind collecting hood 9, and wave motion is generated in the duct 8. A plurality of vibration type electromotive bodies 18 and 18 installed onto the inner wall of the duct 8 are driven by the wind pressure due to the wave motion.