PURPOSE: To obtain a friction gearing allowing a moderate slip at the overloaded time and enabling highly accurate positioning using magnetism by providing a motive power roll with magnetic force so as to attract a passive body to the motive power roll by the magnetic force, and transmitting power by the generated friction holding force.

CONSTITUTION: A magnetic pulley 1 is provided with magnetic pole plates 4, 5 made of ferromagnetic material fixed to both sides of a disc magnet 3 magnetized in such a way that the S-pole appears on one side and the N-pole appears on the other side, and the peripheral surface of the magnetic pole plate 4 is made the S-pole and that of the magnetic pole plate 5 is made the N-pole. The peripheral surface of the magnetic pulley 1 is recessed into circular arc shape of the same diameter as that of a rail 2 so as to correspond to the circular cross section shape of the rail 2, and the rail 2 is formed into a round bar made of ferromagnetic material. The rail 2 is attracted to the magnetic pulley 2 by the magnetic force generated from the magnetic pole plates 4, 5, and when the magnetic pulley 1 is rotated receiving the torque on the drive source side, the rail 2 is conveyed by the frictional force generated by the attractive force of the rail 2 to the magnetic pulley 1.