To provide a superconducting acceleration cavity of which, total size is made small and the cost of equipment and operation cost is reduced.

A cold storage refrigerating machine 11 for the cavity, generating cryogenic temperature of 4K for turning an acceleration cavity main body 2 into as superconducting state, is mounted to an adiabatic vacuum tank 7, and a conduction body 12 for the cavity, conducting cryogenic temperature of the cold storage refrigerating machine 11 to the acceleration cavity main body 2, is thermally connected between the acceleration cavity main body 2 and the cold storage refrigerating machine 11. A conduction body 14 for conducting the cryogenic temperature of a cold storage refrigerating machine 13 for shielding to a radiation heat shield is thermally connected between the radiation heat shield and the cold storage refrigerating machine for shielding.