A device (1) for generating energy on the basis of wave motion comprises a rotatably arranged basic body (10); an elongated, rod-shaped body (20) which is connected to the basic body (10), and which has buoyancy with respect to sea water; an arm (30) which extends between the basic body (10) and the rod-shaped body (20) and interconnects these two bodies (10, 20); and a main shaft (40) which is connected to the basic body (10) for the purpose of being driven by the basic body (10). The rod-shaped body (20) is destined to be moved in and out of the water under the influence of wave motion, and of a rotary movement of the basic body (10), which performs a flywheel function during operation of the device (1). Due to this, the said rotary movement can be maintained.
