The computed result for a stress response value sometimes has considerable errors in the conventional mode superposition method, even if the eigenfrequencies used in the computation cover the frequency components of external loads. A new method improving on the conventional method has already been presented in the previous reports. In that method, adding to eigenvectors, new vectors obtained from static deformation vectors caused by external load vectors are supplemented. In this paper, the new method is applied to frequency response analysis, and two examples are discussed: (1) a simply supported beam and (2) a frame in the shape of an arch. By the new method, the calculated results are almost equal to the exact solution, while by the conventional method, the calculated results greatly differ from exact solution in some cases. In this new method, it is sufficient to consider the eigenmodes of frequency three times higher than that of the externalload.