A method to estimate a collision point on a metal rod is presented, which is based on spectral analyses of the signal detected by a single accelerometer attached to the rod. First, the transfer function from a forcing point to the detector is derived, where space‐variant and dispersive characteristics of the rod are taken into consideration in connection with varying diameter, the change of surrounding condition along the axis, and various transmission and reflection loss characteristics. Then an algorithm to estimate collision point is derived by using the obtained transfer function. The fundamental experimental results obtained by using a 17S aluminum rod of 2003 mm length and 10 mm diameter show that the estimated positions agree with the actual collision positions with a precision of less than 1 cm [O. Ikeda, T. Sato, J. Yamamoto and A. Manabe, J. Acoust. Soc. Am (to be published)].