The mass, the damping and the stiffeness matrices in the equation of vibration are called as the characteristic matrices of a vibration system. In this paper, a new method to identify the characteristic matrices from the response of the vibration system (transfer function) is proposed. In this method, the initial value of characteristic matrices are estimated by the 1st report of Ookuma and Nagamatu, and modified so as to minimize the error between the actual and the estimated transfer function. This modification is iterated, and stopped when the error becomes minimum or the curve fit of the transfer function is sufficient. In order to confirm the accuracy of the proposed method, the transfer function is calculated using the given characteristic matrices, and from its transfer function the characteristic matrices are again identified. The identified characteristic matrices are compared with the original ones, and a good agreement can be seen between them when the transfer function contains sufficient information about the vibration system. When the transfer function containing insufficient information about the vibration system is used for identification, the fitness of transfer function is found be good. However the identified characteristic matrices are considerably different from true matrices.