To provide a wind power generation device capable of highly efficiently generating electric power with a simple structure, capable of narrowing the installation area, reducing restriction of an installation place, and capable of coping with a breeze.

This wind power generation device 1 has a wind receiving blade 10 having a structure of doubly folding a substantially trapezoidal plate member mutually different in the length of the opposed short sides and having its length extremely longer than the length of the short sides in its width direction at a predetermined angle θ, and a power generation part generating electric power by vibration of the wind receiving blade 10. The wind receiving blade 10 torsionally vibrates by receiving wind power, and a piezoelectric plate generates electric power by deflecting. A plane including a plate of the power generation part and the wind direction are parallel, and since this device is arranged so that its vibration direction becomes a substantially right angle to the wind direction, electric power can be further efficiently generated.