To freely move a joining device of a welding torch, a probe for friction agitation joining, etc., by fixing joining members to a joining position while sucking/holding with a vacuum type suction body.

A backing member 4 and a support base 5 are arranged at a prescribed distance as corresponding to a width of a joining member 1, a suction body is arranged as setting its sucking face 21 upward near the backing member 4. The sucking face 21 of a vacuum suction body is brought into tight contact with the joining member 1, a vacuum chamber 20 is sealed. The joining member 1 is held with the vacuum suction body as evacuating an inside of the vacuum chamber 20 by an evacuating device. By imparting force in the butting direction from the vacuum suction body to the joining member 1, the joining member 1 is fixed at a butting state with the other joining member. The joining member 1 fixed to a butting state is subjected to friction agitation joining by a joining device 3, joining is easily conducted. By this method, fixing made surface and joining defect is prevented.