PURPOSE: To perform water-breaking work as well as hydraulic power generation by a method in which a pump to be driven by the movement of tidal wave is provided between a block with a waterway and a water-breaking mechanism provided in a rocking manner to the block and water is pumped up to the waterway by the pump.

CONSTITUTION: When a water-breaking mechanism D receives transverse wave from the direction of X, a wave riding plate 12 with a float 14 rides on the tidal wave and pushes a water-breaking plate 11. Then, a cylindrical stopper 33 goes into a position 33', a valve 36 is opened, and the sea water is pushed up and discharged through a conduit 38 to a waterway 1. At the same time as transverse wave is bent downwards by the wave riding plate 12 and goes into a cavity 2, the wave-breaking plate 11 also goes into the cavity 2, whereby the water level is doubly raised, the upper edge W of the float 23 goes up to the position W', the valve 24 is closed, the valve 22 is opened, and water is discharged through the conduit 21 to the waterway 1. When the transverse wave disappears, the wave-breaking plate 11 moves to the position 11' and thereby the sea water is smoothly sucked into cylinders 34 and 25.