Abstract: The present wave-activated power generator includes a main body floatable in the water surface and an air chamber is formed in the main body. An operating passage is formed as extending from the air chamber with its open end submerged under the water; on the other hand, there is provided a guide passage communicating the air chamber to the atmosphere via a power generating means, whereby, due to the motion of the water column inside the operating passage, there is formed an air flow from the air chamber to the atmosphere through the guide passage thereby driving the power generating means. The operating passage of the present wave-activated power generator is bent approximately in the shape of "L" with its open end provided as oriented toward the downstream direction with respect to the advancing direction of waves, so that it is structured to promote the motion of the water column inside the operating passage due to wave motion.