PURPOSE: To reduce or prevent the bias or the sideway rocking of a magnetic rotor, in a magnetic force transmitting mechanism.

CONSTITUTION: In a magnetic force transmitting mechanism which transmits the torque of one magnetic rotor 5 to the other magnetic rotor 3 through a magnetic rotor 6 by arranging at least two pieces of magnetic rotors 3 and 5 made of magnetic materials apart from each other on parallel centers of rotation, and providing said magnetic rotor 6 being positioned between the magnetic rotors 3 and 5 and also being attracted to the peripheries of these magnetic rotors 3 and 5 by magnetic force, unmovable members 10 and 11 are arranged in opposition to at least one side of the electromagnetic rotor 6. Furthermore, a projection 12 is provided at least one side of the magnetic rotor 6 or at one side, opposed to the magnetic rotor 6, of at least one unmovable member 10 or 11.