PURPOSE: To simplify a control system and improve controllability in a device using an electroviscous fluid variably controlled in viscosity by applying voltage from an electrode by suppressing the change of viscosity caused by the temperature of the electroviscous fluid, and forming the control system without taking account of the change of viscosity caused by temperature.

CONSTITUTION: An electroviscous fluid device is provided with heaters 8 for heating an electroviscous fluid, and a temperature sensor 11 for detecting the temperature of the electroviscous fluid. The heaters 8 are controlled in such a way that the temperature of the electroviscous fluid detected by the temperature sensor 11 becomes the specified temperature.