PURPOSE: To obtain the supply and exhaust of refrigerant required upon increase in size by providing at least one rotatable intermediate cylinder between the rotary shaft and the stationary part of a superconducting rotary electric machine, and providing sealing mechanisms between the shaft and the stationary part, the cylinder and between the cylinders.

CONSTITUTION: A casing 6 as a stationary part is provided at the end of a rotary shaft 1 via bearings. An intermediate cylinder 20 is provided between the shaft 1 and the casing 6. Sealing mechanisms 23 are provided between the cylinder 20 and the shaft 1 and the casing 6. The cylinder 20 is rotated at the lower rotating speed than the rotating speed of the shaft 1, and the relative peripheral speed at the bearings 21 and the mechanism 23 is reduced. Thus, even if the outer diameter of the shaft 1 is increased upon increase in the size so that the peripheral speed of the outer diameter of the shaft is accelerated, the frictional loss can be reduced by the deceleration at the cylinder 20, and the supply and exhaust amounts of the refrigerant required can be obtained.