Abstract: The present invention pertains to a device of a floating wave power plant. More precisely, the invention pertains to a submerged frame structure with an attached ballast body as an element in a floating wave power plant. The frame structure and thereby the wave power plant is preferably anchored to the sea bottom. The wave power plant comprise several pumping cylinders (4) connected to buoyancy elements (5) via connecting elements, which buoyancy elements (5) under the action from waves move the pumping cylinders in full or partial pumping strokes. Furthermore, the pumping cylinders are connected to the submerged frame structure (3), and said frame structure is connected to one or more ballast bodies via a number of connecting elements (2).