To provide a wave-activated power generation device with high operation rate using Magnus effect.

Operation adapted to various wave sizes and periods is necessary for stably supplying electric power from wave energy which considerably fluctuates according to conditions of climate, etc. The device is a floating type wave-activated power generation device which carries out power generation by relative movements of fluid in the sea generated by moving the device itself up and down by vertical movements of the sea surface wave. The Magnus effect of rotation of blades is used for rotating a power generation turbine. Changing rotation speed of the blades makes it possible to adjust torque of the power generation turbine, and stable operation can be expected in various wave conditions. Though the moving direction of wave periodically varies, the rotation direction of the turbine can be kept constant by varying the rotation direction of the blades in synchronization with the wave.