PURPOSE: To increase the strength at the junction part of the rear end part of the preceding bar and the tip part of the succeeding bar by performing the flame coating of the mating face of the preceding bar rear end part and succeeding bar tip part with the gas from an injection nozzle, thereafter by performing the pressurizing and joining with a metal die.

CONSTITUTION: LPG and oxygen are injected from a gas injection nozzle 15 with moving a truck 10 in the progressing direction of bars 6, 7 by overlapping the preceding bar 6 rear end part and succeeding bar 7 tip part between the upper and lower metal dies 12, 13 of the bar junction equipment. Both parts of the mutually opposing faces of the preceding bar 6 rear end part and succeeding bar 7 tip part or either one face is heated and the overlapping part of the bar 6, 7 is joined with pressure by the upper and lower metal dies 12, 13 by descending the upper die 12 by a fluid pressure cylinder 11.