Magnetic coupling device having first and second rotating members arranged with opposing interaction surfaces

A reduced-size magnetic coupling device includes a first magnet group having a plurality of first magnets arranged on an interaction surface at equal intervals in the direction of the circumference about the rotation axis; a second magnet group having a plurality of second magnets arranged on an interaction surface at equal intervals in the direction of the circumference about the rotation axis and in positions in the vicinity of the rotation axis; and a third magnet group having a plurality of third magnets that are arranged at equal intervals in the circumferential direction about the rotation axis and in positions outward with respect to the second magnets. The third magnets have an area approximately equal to that of the second magnets. Each third magnet has a magnetic pole different from that of the second magnet that is positioned between the third magnet and the rotation axis.