PURPOSE: To reduce the evaporation of cryosubstances such as liquid He.

CONSTITUTION: A plurality of permanent magnets 14 are disposed on the inner surface of a keeping container 3 and permanet magnets 15 repulsive to the permanent magnet 14 are disposed inside the lower part of a shroud 6. That is, the keeping container 3 is supported under the radial contact-free condition by the repulsion between the permanent magnets 14, 15. Also, the keeping container 3 is axially (vertically in the drawing) is supported by stretching a low heat conduction wire 16, for example ceramic wire between a small diameter part 3a and the inner surface of the shroud 6. Thus, the evaporation amount of liquid He 2 can be reduced by reducing thermal inflow due to the contact of the liquid He 2 with a solid body.