PROBLEM TO BE SOLVED: To provide a joining device and a method for manufacturing a long material in which strength of a join part is not reduced and uniform joining free from deposition of a molten material on an outer periphery of the join part can be obtained in a short time.SOLUTION: In the joining method for manufacturing the long bar-shaped join material from a short bar-shaped material to be joined, a heating tool which pressure-holds a join surface of the short material to be joined and surrounds a periphery of the join surface without contacting the same is provided. The join surface is indirectly heated to a temperature which makes joining possible by electrically heating the heating tool, an electrical discharge is performed on the join surface by energizing the material to be joined from a power source for joining, and the join surface is joined with activation of the join surface and with Joule heat by energizing.
