A rotor of a synchronous motor includes a rotating shaft, a plurality of segments, a plurality of permanent magnets, and a field coil. The segments are located radially outward of the rotating shaft and arranged in the circumferential direction of the rotating shaft at a predetermined pitch with spaces formed therebetween. Each of the segments has a recess making up a magnetic reluctance portion and an opposite pair of ends making up salient-pole portions. Each of the permanent magnets is disposed in one the spaces between the segments with a predetermined orientation of its N and S poles. The field coil is wound around the segments to extend in the circumferential direction of the rotating shaft through the recesses of the segments. The field coil creates, when energized with DC current, magnetic flux which magnetizes the pair of ends of each of the segments in opposite directions.