An object is to propose a fluid handling device for liquid hydrogen that prevents evaporation of liquid hydrogen, and moreover affords excellent heat insulation without liquefying oxygen in the vicinity. In a fluid handling device for liquid hydrogen, piping sections (1) have a heat insulation structure, a swivel joint section (2) is configured with helium gas sealed into a boundary relative-rotation section (6) between an outer ring section (3) and an inner ring section (4) with a bearing section (5) interposed, and moreover, between an outside-air-contacting wall section (7) that is in contact with the outside air and a liquid-hydrogen-contacting wall section (8) that is in contact with liquid hydrogen, a vacuum section (9) extends in the axial direction and moreover a heat-conducting extended path section (10) is provided with one end connected to the outside-air-contacting wall section (7) and the other end connected to the liquid-hydrogen-contacting wall section (8), extending the heat conduction distance between the outside-air-contacting wall section (7) and the liquid-hydrogen-contacting wall section (8), and reducing heat conductivity between the outside-air-contacting wall section (7) and the liquid-hydrogen-contacting wall section (8).

A rotary joint for maintaining a cryogenic supplying refrigerant comprises a vacuum use cylindrical shaft supported in rotatable condition, a rotary seal ring fitted to an outer circumferential face with a space, a stationary seal ring provided at both sides of the respective rotary seal rings, a resilient bellows to press the stationary ring resiliently to the rotary seal ring side, a spaced fluid passage formed between the respective resilient bellows, a second fluid passage communicating with the spaced fluid passage, a connecting fluid passage communicating with the second fluid passage, a first pipe communicating through the spaced fluid passage, a connecting cover having a suction bore for vacuumizing and a magnetic fluid seal device having a projection constituted as multiple gaps corresponding to a pressure of the vacuumizing.