PURPOSE: To aim at attainment of a desired stabilized transmitted torque by providing one of an internal cylinder linking with a shaft and an external cylinder installed outside the internal cylinder through a gap with electromagnets, and providing the other one with magnet particles contained therein in its flowable condition.

CONSTITUTION: An inner cylinder 22, which is hollow inside and contains magnet particles 27 therein in a fluidized condition, is to be provided on the outer side of a shaft 21 in one unit and also provided on the outer side of the inner cylinder 22 through a prescribed gap in a freely rotatable manner is an outer cylinder 26 whose internal circumference surface is formed with electromagnets arranged so that the N pole and the S pole will alternate in the circumference direction. Consequently, the torque is generated by the hysteresis caused by the independent rotation of the magnet particles 27 making the transmitted torque stabilized for a long period of time and attaining the desired torque.