PROBLEM TO BE SOLVED: To provide a welded structure of tubular members and a bending device which can suppress the increase of the outer diameter of nodal rings and improve the strength against tilting of the wire insertion direction.SOLUTION: The welded structure of tubular members is formed by welding a second metal tubular member to the inner periphery of a first metal tubular member, the outer diameter of the second tubular member being smaller than the inner diameter of the first tubular member. The structure includes a plurality of welds which join the first and second tubular members such that a part of the first tubular member and a part of the second tubular member are fused and solidified together and that the surface formed by the fusion and solidification from the inner peripheral surface of the first tubular member to an end surface of the second tubular member is smoothly curved in a continuous manner. A part of each weld is located outside a projected region where the second tubular member is projected on the outer surface of the first tubular member.SELECTED DRAWING: Figure 5【課題】節輪の外径の増大を抑制し、かつワイヤ挿通方向の煽りに対する強度を向上することができる筒状部材の溶接構造、および湾曲装置を提供する。【解決手段】金属製の第１の筒状部材の内周に、該第１の筒状部材の内径よりも小さい外径を有する金属製の第２の筒状部材を溶接してなる筒状部材の溶接構造であって、第１の筒状部材の一部と第２の筒状部材の一部とが溶融固化してなり、第１の筒状部材の内周面側から第２の筒状部材の端面にかけて溶融固化してなる表面が滑らかに連続する曲面をなし、第１および第２の筒状部材を接合する複数の溶接部、を備え、各溶接部の一部は、第１の筒状部材の外表面において第２の筒状部材を投影した投影領域の外側に位置する。【選択図】図５
