PURPOSE: To provide a superconducting rotor which has a current lead which is provided to connect a field winding to a slip ring electrically in order to improve the stability of a superconducting generator and which does not cause a dielectric breakdown even if a high voltage is applied to it.

CONSTITUTION: A superconducting rotor has a current lead 3 which connects a superconducting field winding to a slip ring 18 provided on the axial end part and which is cooled by introducing low temperature helium gas in a generator into it and a protective pipe 12 which is provided outside the current lead 3 with an insulating layer 2 therebetween and supports the current lead 3. In the superconducting rotor like this, a sealing mechanism 20a which prevents the low temperature helium gas 1b in the generator side from leaking into the current lead 3 through a gap between the insulating layer 2 and the protective pipe 12.