The purpose of this is to establish a measurement method for the fluid force acting on axial turbo machines. The method aims to evaluate the fluid forces as divided into two components, i.e., exciting force and damping force. This method is found to be satisfactory in comparison with other ordinary methods of estimating the fluid force acting on a column test piece in a wind tunnel. According to the results of a test using an axial compressor model with flat blades, the method can quantitatively predict the fluid force acting on rotating blades. Moreover, it is applicable to actual machines.