PURPOSE: To provide the joining method between a copper tube for joining and flange as not depending on experience and skill of worker and obtaining highly reliable joining.

CONSTITUTION: In the method to join a annular flange 2 to the end part of a copper tube 1 for cable joining in split form in the direction orthogonal to the axis, the end part of the copper tube 1 is positioned on the inner peripheral part of the annular flange 2, a high frequency induction heating device 10 is placed inside the end part of copper tube 1, heating from the inner peripheral part, the brazing filler metal placed between the inner peripheral part of the annular flange 2 and end part of copper tube 1 is melted and brazed.