To provide a magnetic power transmission system which is capable of improving the power transmitting efficiency and the power transmitting capacity while maintaining the advantageous effects obtained by performing power transmission by magnetic forces, and reducing manufacturing costs of the system. A magnetic power transmission system 1 is comprised of an outer rotor 11 including a plurality of circumferentially arranged left and right permanent magnets 11c, an inner rotor 12 including a plurality of circumferentially arranged left and right permanent magnets 12c, and an intermediate rotor 13 including a plurality of circumferentially arranged left and right soft magnetic material elements 13d, 13e. When each of the left and right permanent magnets 11c and 11c and each permanent magnet 12c are in an opposed position opposed to each other, if the magnetic pole of the left permanent magnet 11c and the magnetic pole at the left-side end of the permanent magnet 12c have polarities different from each other, the magnetic pole of the right permanent magnet 11c and the magnetic pole at the right-side end of the permanent magnet 12c have the same polarity. Further, when one of the soft magnetic material elements 13d and 13e is between permanent magnets 11c and 12c, the other is between two permanent magnets 11c and 12c adjacent to each other.