To provide a DC motor that is manufactured at low cost by a simple constitution without needing a complicated control circuit, has a long service life, and is reduced in size and thickness.

Either of a rotor 1 and a stator 3 comprises a permanent magnet 5, and the other comprises a plurality of magnetic poles 2 constituted of electromagnets. The plurality of magnetic poles 2 are composed of 2n or more magnetic pole groups G having a plurality of magnetic poles that are excited to the same polarities, the magnetic pole groups G adjoining to each other in the circumferential direction around a shaft core are constituted so as to be excited to different polarities at the magnetic poles 2, the strength of a magnetic field of each of the plurality of magnetic poles 2 that are possessed by the magnetic pole groups G is made successively larger at each magnetic pole toward a rotor rotative direction or a reverse rotative direction, and thereby a gradient of the magnetic field is generated.