A structural hydroformed joint member has projecting portions (30a, 30b) formed integrally on an outer peripheral face of a hollow main tube part (20) by hydroforming an element tube with an outside diameter D. In this case, both intersecting planes (35a, 35b), which are projecting planes of end faces (33a, 33b) of the projecting portions (30a, 30b) toward the main tube part (20), share a plane perpendicular to the main axis (40) of the main tube part (20) only in portions (36a, 36b) of the intersecting planes (35a, 35b). At that time, by setting areas of the portions (36a, 36b) to 30% or more and 90% or less relative to an area of each of the intersecting planes (35a, 35b), a projecting height of each of the projecting portions (30a, 30b) is 0.3D or higher for functioning as a joint.