PURPOSE: To provide a superconducting DC machine which restrains a superconducting coil from being quenched and which can increase an output per volume.

CONSTITUTION: A shaft 41 for an armature 31 is arranged at right angles to the central axis of a cylindrical superconducting coil 1. At least two armature coils 711 are wound on the armature, and only the armature coil which is situated near the central axis of the superconducting coil is connected selectively to an external circuit by a commutator 8 and a brush 9. Auxiliary superconducting coils 11 which are used to compensate the reaction of the armature are arranged at the upper-side end part and the lower-side end part of the superconducting coil. When the auxiliary superconducting coils are connected electrically in parallel with the superconducting coil and an electric heater for transition of a conduction state is installed, the auxiliary superconducting coils function as a switch for a persistent-current closed circuit.