To improve torque transmitting performance of a device for transmitting torque by using the fluid of a torque converter, a liquid clutch or the like as a medium, by inhibiting fluid slip, and to remove defects caused by fluid slip.

The fluidized mixture of high density is prepared by mixing sand-like steel spherical particles of a size large enough to freely pass between blades, into the machine oil. The fluidized mixture of high density is used as the medium for transmitting torque, thus the fluid slip is reduced, torque transmitting performance is improved, and the defects in the torque transmitting device using only the machine oil as the medium for transmitting torque, is removed.