Abstract: A device for converting wave energy into electrical energy has a sliding mass, a guide for the sliding mass, an electric generator provided with a rotor, a rotor shaft integral with the rotor, a first mechanism that connects the sliding mass to the rotor shaft and can convert the motion of the sliding mass on the guide into a rotational motion of the rotor shaft, and a second mechanism interposed between the first mechanism and the rotor shaft to provide the rotor with an one-way rotation, regardless of the direction of motion of the sliding mass. A floating apparatus may include such a device.