PURPOSE: To prevent occurrence of noise by composing a motor case of superconducting ceramics.

CONSTITUTION: In a coreless DC motor, a plurality of formed windings 9 integrally molded with plastic molding material 11 at a shaft 8 and a commutator 10 are mounted on a shaft 8 to form a rotor, a magnet 15 is secured to a frame 14, a yoke 16, a brush 17 and the like are provided. In this case, an upper motor case 1, a lower motor case 2, and a magnetic path forming disc 3 are provided, and formed of superconducting ceramics. The cases 1∼2 are coated with oil 5, grease 7 to be also used as a radial bearing 4, a thrust bearing 6 in contact with the shaft 8. Thus, the bearings 4, 6 are immersed with the oil 5, the grease 7 in the porous ceramics, thereby increasing the life.