Provided is a junction structure or the like with which it possible to firmly join together tubes formed of mutually different metals or alloys. A junction structure is equipped with a needle tube (63) made of a first metal or alloy, a needle (62) made of a second metal or alloy different from the first metal or alloy, a coupling member (66) forming a cylinder inside which a passage (66a) into which the needle tube (63) and the needle (62) can be inserted is provided, the coupling member (66) being provided on a side surface with a through hole (66b) penetrating from the outer portion of the coupling member (66) to the passage (66a), and a brazing material (67) injected from the through hole (66b) in a state in which the end surfaces of the needle tube (63) and the needle (62) are in contact in the passage (66a) for joining the coupling member (66) to the needle tube (63) and the needle (62)； the second metal or alloy is more readily oxidized than the first metal or alloy during soldering using the brazing material (67), and the contact position of the needle tube (63) and the needle (62) is located on the needle (62)-side from the through hole (66b) along the direction in which the needle tube (63) and the needle (62) extend.L'invention concerne une structure de jonction ou similaire, avec laquelle il est possible de relier fermement ensemble des tubes formés de métaux ou d'alliages mutuellement différents. Une structure de jonction comprend un tube d'aiguille (63) constitué d'un premier métal ou alliage, une aiguille (62) constituée d'un second métal ou alliage différent du premier métal ou alliage, un élément de couplage (66) formant un cylindre dans lequel un passage (66a), dans lequel le tube d'aiguille (63) et l'aiguille (62) peuvent être insérés, est formé, l'élément de couplage (66) étant situé sur une surface latérale ayant un trou traversant (66b) pénétrant de la partie externe de l'élément de couplage (66) jusqu'au passage (66a), et un matériau de brasage
