To provide a superconducting rotating electric machine which inhibits the freezing of a seal member and improves a rate of recovery of a cooling medium to keep a cooling medium cooling cost low.

The superconducting rotating electric machine 1 includes a rotor 1 having a superconducting coil 150, an outer rotating tube 30, an outer fixed tube 50, and a buffer means 60. An outer seal member 80 is disposed between the rotating tube 30 and the rotating tube 50. The buffer means 60 partitions a buffer space 61 opposite to the internal spaces 31 and 51 of the tubes 30 and 50 with respect to an outer seal 80, from an outside space 2 of the rotating electric machine 1. The rotating electric machine 1 includes a cooling medium circulator 90 which supplies or recovers a cooling medium to or from the inside of the rotor 1 via the internal spaces 31 and 51 of the tubes 30 and 50, and a gas supplier 100 which supplies a gas having a freezing point lower than the temperature of the outer seal member 80 so as to raise the pressure of the buffer space 61 above the pressure of the outside space 2.