The present invention provides a rotary joint which is available to maintain a cryogenic supplying refrigerant which flows in a fluid passage by a vacuum thermal insulation so that a cooling portion is cooled certainly. The rotary joint of the present invention comprises a vacuum use cylindrical shaft (10) supported in rotatable condition to an inner circumferential face of a main body having a vacuum passage, a rotary seal ring (1A) fitted to an outer circumferential face with a space and provided with seal faces at both end faces, a stationary seal (2A) ring provided at both sides of the respective rotary seal rings and provided with a counter seal face contacting hermetically with the seal face, a resilient bellows (2B) joint with a circumferential face of end portion of the stationary seal ring to press the stationary ring resiliently to the seal face side, a spaced fluid passage (20B) formed between the respective resilient bellows for passing through the supplying refrigerant by joining with a first fluid passage providing the supplying refrigerant, a second fluid passage (20C) communicating with the spaced fluid passage provided at the rotary seal ring, a connecting fluid passage (20D) communicating with the second fluid passage, a first pipe (20E) communicating through the spaced fluid passage so as to provide the supplying refrigerant to be vacuum thermally insulated in the vacuum use cylindrical shaft to a cooling portion, a connecting cover (42) having a suction bore for vacuumizing in the vacuum use cylindrical shaft and a magnetic fluid seal device (40) having a projection constituted as multiple gaps in the axial direction corresponding to a pressure of the vacuumizing.