This paper describes the comparison between analysis and measurement of aerodynamic admittance functions for lift and moment of bluff bodies with various aspect ratio and with triangular fairing. The authors have proposed a method for estimating aerodynamic admittance function using flutter derivatives (i.e., FDs). The estimation method is applicable to bluff bodies as shown in this paper. The direct measured aerodynamic admittance functions for the bluff bodies are in good agreement with identified ones in FDs. However, the obtained aerodynamic admittance functions have different tendency with Sears' function. It was obvious that the difference between the obtained ones and Sears' function was due to the different growth of transient aerodynamic force (i.e., identified equivalent Wagner's function).