A joint structure including a first member made of a metal material, a second member made of a material that is difficult to be welded to the first member, and a third member made of a filler material and welded to the first member, wherein the first member and the third member are ferrous metal materials and the second member is a nonferrous metal material or a resin material; the first member, the second member, and the third member being joined together, the second member including a through-portion penetrating toward the first member, the third member being welded to the first member through the through-portion, at least one of overlapped surfaces of the first member and the second member including a recess formed into a space separate from the through-portion, the recess being recessed so as to surround an entire periphery of the through-portion, the recess being formed into a space separate from a welded part that is a welding site where the first member and the third member are welded together, the recess being recessed so as to surround an entire periphery of the welded part, characterized in that at least one of the first member or the second member including an injection hole communicating with the recess, and the recess being provided with a sealing material injected from the injection hole, the sealing material closing a gap between the overlapped surfaces of the first member and the second member. wherein the first member and the third member are ferrous metal materials and the second member is a nonferrous metal material or a resin material; the first member, the second member, and the third member being joined together, the second member including a through-portion penetrating toward the first member, the third member being welded to the first member through the through-portion, at least one of overlapped surfaces of the first member and the second member including a recess formed into a space separate from the through-portion, the recess being recessed so as to surround an entire periphery of the through-portion, the recess being formed into a space separate from a welded part that is a welding site where the first member and the third member are welded together, the recess being recessed so as to surround an entire periphery of the welded part, characterized in that at least one of the first member or the second member including an injection hole communicating with the recess, and the recess being provided with a sealing material injected from the injection hole, the sealing material closing a gap between the overlapped surfaces of the first member and the second member. the second member including a through-portion penetrating toward the first member, the third member being welded to the first member through the through-portion, at least one of overlapped surfaces of the first member and the second member including a recess formed into a space separate from the through-portion, the recess being recessed so as to surround an entire periphery of the through-portion, the recess being formed into a space separate from a welded part that is a welding site where the first member and the third member are welded together, the recess being recessed so as to surround an entire periphery of the welded part, characterized in that at least one of the first member or the second member including an injection hole communicating with the recess, and the recess being provided with a sealing material injected from the injection hole, the sealing material closing a gap between the overlapped surfaces of the first member and the second member.