A tube connection structure includes a joint body and a coupling member. The coupling member has a fastening part threaded with the joint body and a tool-engaging part gripable with a fastening tool. The coupling member and the joint body are-configured such that the tool-engaging part is separated from the fastening part after the coupling member is mounted to the joint body. The joint body and the coupling member have a threading contact part. The components of the threaded contact part are in contact with each other so that the threading of the coupling member over the joint body is limited before the tool-engaging part is separated from the fastening part.