A piezoelectric power generating device is provided which is capable of extracting a large amount of power without an increase in device size, even when applied with vibration of low frequency or weak external force, and which is easy to manufacture.The piezoelectric power generating device includes a piezoelectric power generating plate including a piezoelectric plate having a polarized regions that are different in polarization direction, and a support member attached to the piezoelectric power generating plate. Further, the piezoelectric power generating plate includes a fixed portion fixed to the support member, a free end displaced relative to the fixed portion when an external forced, such as a vibration forced, is applied, and a cutout located between the fixed portion and the free end.