To provide a simple-structure and low-cost wave force power generating buoy capable of effectively utilizing wave force of vertically and laterally moving waves for automatically generating power so as to let a light emitting body to emit light throughout the year without possibility of overcharge or over discharge.

In this wave force power generating buoy composed of a floating body provided with a light emitting body on top of a water-tight case, a battery charger disposed inside the floating body, and a piezoelectric power generator connected to the battery charger, the piezoelectric power generator is composed of a layered piezoelectric ceramic plate comprising two plate-shaped piezoelectric ceramic elements jointed with each other with their polarization set to be inverse to each other, so wave force generated by vertical and lateral movement of wave surfaces hits one surface or both surfaces of the piezoelectric ceramic to generate power.