A method for assembling rotors which is applicable to a large axial gap type permanent magnet rotating machine is provided.A permanent magnet rotating machine comprising: a rotating shaft; at least two rotors comprising a table-like structure and permanent magnets attached thereto, the table-like structures being connected to the rotating shaft and being disposed in an axial direction of the rotating shaft; and a stator comprising a table-like structure and stator coils around which a copper wire is wound, said stator being disposed in a gap formed by the rotors so that the stator being separated from the rotating shaft, is manufactured by the following steps of. assembling the two rotors such that a predetermined gap is formed therebetween; and mounting the magnets on the table-like structures by inserting the magnet from the radially outer side of the table-like structures towards the center of the rotation with the assembled state being maintained.