Tidal power generator

Power generation technology using tidal power or wave power is provided, especially as related to power generation technology using a piezoelectric element. Power generation technology includes a power generation device for effectively generating electric power in water or on a ship with the use of tidal power or wave force and having power generation modules (5a, 5b) having a piezoelectric element (14) put between plates (1a, 1b, 1c). The plates are placed between two flanges (9b, 10) fixed to a rod (3) penetrating the plates. When the rod (3) inclines due to a water flow, the piezoelectric element (14) is compressed by the two flanges (9b, 10) which generates electric power. Moreover, when the rod (3) is restored from due to reduction of the water flow, thickness of the piezoelectric element (14) is restored which also generates electric power.