To provide a joining structure that joins at least two or more building members together, in which jig insertion holes into which a joining jig is inserted are provided in the building members, respectively, the joining jig is inserted into the jig insertion holes and an adhesive that fixes the joining jig and the building members together is filled in the jig insertion holes, the joining jig to be inserted into the jig insertion holes includes a cylindrical main body, an intermediate shaft portion, and threaded end portions, and the threaded end portions are provided by rolled threads.