PURPOSE: To obtain a rotor, of a superconducting rotating electric machine, in which a high-reliability quenching protective system can be constituted, in which the diameter of a driving shaft is not limited and which can achieve the large capacity of the rotating electric machine.

CONSTITUTION: In the rotor of a superconducting rotating electric machine, a superconducting field winding 4 is wound on a low-temperature rotor 1 having a refrigerant storage part at the inside, and the superconducting field winding 4 is cooled by a refrigerant liquid which has been stored in the refrigerant storage part. Consequently, a quenching detector which detects that the superconducting field winding 4 has been quenched is installed at the inside of the rotor, and a signal transmission apparatus which transmits, in a noncontact manner, a quenching detection signal as a signal indicating two states of whether it is quenched and not quenched from the side of a rotation part to the side of a standstill part and which is composed of a transmitter 20 and a receiver is installed.