<p>The electroviscous fluid is a suspension composed of a finely divided dielectric solid dispersed in an electrically nonconductive oil. The viscosity of the fluid increases swiftly and reversibly under an influence of electric field applied thereto and the fluid turns to a state of plastic or solid when the influence is sufficiently strong. The electroviscous fluid of the present invention comprises 1- 60% by weight of a dispersed phase of carbonaceous particulates having average particle size of 0.01-100 micrometer, and 99-40% by weight of a continuous liquid phase of an electric insulating oil having a viscosity of 0.65-500 centistokes at room temperature. The electroviscous fluid exhibits an excellent electroviscous effect even at a high temperature with a low electric power consumption together with maintaining the improved electroviscous effect for a long period of time.</p>
