To provide a homogeneous electroviscous fluid which is stable against the repetition of application of a voltage or the application of a voltage for a long period of time and can be utilized in an actuator for absorption of vibration or mechanical control.

This electroviscous fluid comprises a diluent (I) with a liq. crystalline group bonded to a flexible molecular chain with a percentage bond of 25 to 80%; a compd. (II) with a liq. crystalline group bonded to a flexible molecular chain with a percentage bond of 5 to 20%; and a diluent (III) not having any crystalline group comprising a flexible molecular chain. Based on 100 pts.wt. in total wt. of the compd. (I) and the compd. (II), the amt. of the compd. (I) is 50 to 80 pts.wt., the amt. of the compd. (II) is 50 to 20 pts.wt., and the amt. of the diluent (III) is 10 to 200 pts.wt.