Abstract: A guide wire includes a wire body having a first wire disposed at a distal end and a second wire joined to a proximal end of the first wire at a joint by welding. The joint is curved. In the joint, at least one component (e.g., Ti) of the material of the first wire decreases toward the proximal end and at least one component (e.g., Fe) of the material of the second wire decreases toward the distal end. When a tensile test is conducted on a region of the wire body including the joint, the region of the wire body has, in a tensile load and elongation diagram, an elastic section extending substantially straight upwardly to the right, a yield section extending substantially horizontally or upwardly to the right from the elastic section, and a substantially straight section extending upwardly to the right from the yield section.