To provide a cover structure for a pipe joint for reliably sealing the opening of a pipe joint when mounting a partitioning cover on the pipe joint as a biting joint while suppressing the deformation of a sleeve, and to provide a partitioning cover to be used for the cover structure, a refrigerating device using the cover structure, and a pipe connecting method.

When mounted on the pipe joint 1, the partitioning cover 2 is held between a joint body 11 and a nut 12 by screwing the nut 12 into the joint body 11. At this time, the partitioning cover 2 is supported not to thrust the sleeve 13. Thus, the mounting of the partitioning cover 2 hermetically seals the opening 1a of the pipe joint 1 while preventing the deformation of the sleeve 13.