PURPOSE: To permit to absorb wave energy efficiently even in case the height of the wave is small by a method wherein a frame is attached inbetween the lower ends of a pair of levers so as to be free of relative oscillation and a pressure receiving plate is hang from the frame so as to be moved in a movement similar to a horizontal movement suitable for shallow waves.

CONSTITUTION: A pair of shafts 12, 13 are supported in the upper part of a water chamber through bearings 14, 15 while the levers 16, 17 are hang from each shafts 12, 13. The frame 20 is attached to the lower ends of each levers 16, 17 so as to be free of relative oscillation while the pressure receiving plate 11 is hang from the central part of the frame 20. The central parts of each levers 16, 17 are connected to hydraulic pressure generating devices 24, 25 through shafts respectively. According to this method, the pressure receiving plate 11 reciprocates almost horizontally by receiving the force of the wave 26, this motion is applied to the frame 20 and each levers 16, 17 swing as dual pendulums, therefore, each hydraulic pressure generating devices 24, 25 are reciprocated almost horizontally and the hydraulic pressure is generated. Thereby, the hydraulic pressure is sent into a hydraulic motor through each pipes 27, 28 and the energy may be extracted.