An adaptive notch filter design that considers the body-bending vibration associated with the attitude control of a solid launcher is discussed. The problem of obtaining a notch filter from a given signal was first formulated as the conventional problem of system identification. Then the proposed adaptive notch filter was developed via the algorithm of Steiglitz-McBride. The new adaptive notch filter exhibits fast convergence speed and an excellent capability to frequency tracking in signals. Applying this adaptive notch filter to the launcher results in stable response characteristics of the attitude control system, which is unstable without adaptation.