A superconductivity rotor has a field coil portion wound with a
superconductivity wire, a support portion for supporting the field coil
portion, torque tubes positioned at both ends of the support portion and
transmitting a torque to an outside from the field coil portion, an inner
casing for housing the field coil portion and the support portion; and an
outer casing for housing the inner casing and the torque tube. The torque
tube consists of a first torque tube positioned at one end of the support
portion and a second torque tube positioned at the other end of the
support portion. The first torque tube is formed into a vessel shape and
has a plurality of engagement holes formed along a periphery thereof so
that it is engaged with an engagement member, and the second torque tube
comprises a disc-shaped structure consisting of plural plates and main
ring-shaped members stacked, and is engaged with an engagement member.