Abstract: In a nutation damper system which includes a pendulum (30, 33, 34, 38) swingable at a natural frequency and a block element (35) which cooperates with the pendulum to damp nutations having a nutation frequency, a control member (40) electromagnetically coupled to the pendulum is provided for varying the natural frequency to a forced frequency substantially equal to the nutation frequency. The control member comprises an electromagnetic coil energized by a control signal having electric current produced by a control signal circuit which is proportional to a square of the nutation frequency. The block element may comprise either a permanent magnet or an electromagnet when a pendulum weight of the pendulum is of an electrical conductor. The electromagnet may intermittently be energized by a power source circuit. Alternatively, the block element may be of an electrical conductor when the pendulum weight is of a permanent magnet.