A rotor for an electric motor (10) includes a magnetic assembly (12) formed into a ring-shaped plate form, a rotor disc (11) for holding an inner periphery of the magnet assembly, and an outer peripheral ring (13) for holding an outer periphery of the magnet assembly. The magnet assembly is composed of first and second main magnets (12A-1, 12A-2) having magnetizations directions that are oriented perpendicularly and having orientations that are opposite one another, and first and second submagnets (12B-1, 12B-2) having magnetization directions that are oriented perpendicularly in a circumferential direction and having orientations that are opposite one another. At least one group of magnets selected from the main magnets and the submagnets has a wedge-shaped planar part. The planar parts of the first and second main magnets and first and second submagnets form the same plane of rotation. The magnets are arranged so that the magnetization directions of adjacent magnets are perpendicular to one another.