Pipe holding connection structure and high frequency antenna device including the same

A pipe holding connection structure which is a portion of a pipe passing through an opening in a vacuum container, through the pipe a fluid flows, the pipe holding connection structure comprising:

• a housing fixed to an outer wall of the vacuum container to air-tightly close the opening and having a through hole and a first female thread part and a second female thread part joined to the through hole therein;
• a first pipe provided inside the vacuum container, wherein through the first pipe the fluid flows, a portion near an end portion of the first pipe passes through the opening in the vacuum container, the first pipe has a locking part near the end portion, the locking part is engaged with an end portion of the housing on the vacuum container side so as to stop outward movement of the first pipe from the vacuum container, the first pipe has a first male thread part on the end portion thereof, and the first male thread part is screwed to the first female thread part of the housing to connect the first pipe and the housing;
• a packing configured to vacuum-seal between the housing and the first pipe;
• a second pipe provided outside the vacuum container, wherein through the second pipe the fluid flows;
• and
• a joint which has a portion connected to an end portion of the second pipe and a second male thread part screwed to the second female thread part in the housing and connects the second pipe to the housing when the fluid has been sealed.