To provide a small sized motor in which a wasteful space generated between a stator core and a housing is used as a path of magnetic flux and output torque is improved.

This motor includes a stator and a rotor provided at the internal side of the stator. The stator includes a cylindrical stator core where a plurality of slots and teeth are alternately formed along the internal circumference of a back yoke and a winding coil wound around the back yoke of the respective slots. The complementary teeth cores are provided to the top surface and bottom surface of the stator core, respectively, to substantially fill a gap between adjacent winding coils.