A method for converting the energy of water waves into electricity by means of a wave power plant, which comprises a floating body, a rotator which is supported on the body and rotates around a rotator shaft which is on average vertical or slightly inclined to the side, a gyro which rotates around a gyro shaft which is on average horizontal, the gyro and the gyro shaft rotating with the rotator around the rotator shaft, and at least one generator, which is connected to rotate together with the gyro or the rotator, the method including the following stages: the floating body is rolled by means of waves in step with the waves the gyro is rotated around the gyro shaft the inclination of the gyro shaft with respect to the horizontal plane is caused as a result of the rolling motion, and the rotation of the rotator is influenced by the torque of the gyro, which follows from the inclination of the gyro shaft, characterised in that by means of the rotator's mass are produced moments rotating the rotator in the same direction at the same stage on the one hand by means of the inclination moment generated by the inclination of the body and gravitation, and on the other hand by means of the acceleration moment generated by the horizontal acceleration of the rotator shaft, that the said inclination and acceleration are caused by rolling the body in a direction deviating from the rolling direction according to the direction of the wave surface, which is achieved by directing the internal flows of the wave at the submerged part of the body, which is a mainly vertical, or when in operation, a wall inclined on average in the incoming direction of the wave, which is transverse to the direction of travel of the waves, that the lower part of the body is influenced by anchor force which takes part in inclining the body and causing acceleration, and that the moment generated by gyro force is used to equalize the said inclination and acceleration moments during the revolution and the kinetic energy of the gyro is used as an energy reserve to equalize the effective output of the wave power plant. the floating body is rolled by means of waves in step with the waves the gyro is rotated around the gyro shaft the inclination of the gyro shaft with respect to the horizontal plane is caused as a result of the rolling motion, and the rotation of the rotator is influenced by the torque of the gyro, which follows from the inclination of the gyro shaft, characterised in that by means of the rotator's mass are produced moments rotating the rotator in the same direction at the same stage on the one hand by means of the inclination moment generated by the inclination of the body and gravitation, and on the other hand by means of the acceleration moment generated by the horizontal acceleration of the rotator shaft, that the said inclination and acceleration are caused by rolling the body in a direction deviating from the rolling direction according to the direction of the wave surface, which is achieved by directing the internal flows of the wave at the submerged part of the body, which is a mainly vertical, or when in operation, a wall inclined on average in the incoming direction of the wave, which is transverse to the direction of travel of the waves, that the lower part of the body is influenced by anchor force which takes part in inclining the body and causing acceleration, and that the moment generated by gyro force is used to equalize the said inclination and acceleration moments during the revolution and the kinetic energy of the gyro is used as an energy reserve to equalize the effective output of the wave power plant.