The purpose of this study is the development of an elastic sensor for the measurement of wall shear stress induced by flow. We used a flexible sensor by MCF rubber. The MCF is named of Magnetic Compound Fluid. This functional material can be measured the force by change of electric conductivity with a deformation. The experiments were carried out with the basis of rotational viscometer. The results with MCF sensor sense the decreasing of wall shear stress with the decelerating the flow gradually. The results suggest the good responsivities for the force measurement.