A member comprising: a first sheet material ; a second sheet material ; a first joint line portion ; a second joint line portion ; and a third joint line portion , wherein a sheet thickness of the first sheet material is equal to or less than a sheet thickness of the second sheet material , the first sheet material and the second sheet material are overlapped with each other, the first joint line portion , the second joint line portion , and the third joint line portion each join the first sheet material and the second sheet material at an interface between the first sheet material and the second sheet material , the first joint line portion includes an A portion whose shortest in-plane distance from the second joint line portion is 20 times or more and 120 times or less the sheet thickness of the first sheet material , the second joint line portion includes a B portion whose shortest in-plane distance from the first joint line portion is 20 times or more and 120 times or less the sheet thickness of the first sheet material , the third joint line portion is in a first region interposed between the A portion and the B portion , a length of a length component of the third joint line portion in the first region in an extension direction of an intermediate line between the first joint line portion and the second joint line portion is 250 mm or more, and characterized in that at least one of the first j oint line portion or the second joint line portion is a curved line and the third joint line portion between the first joint line portion and the second joint line portion is also a curved line. a first sheet material ; a second sheet material ; a first joint line portion ; a second joint line portion ; and a third joint line portion , wherein a sheet thickness of the first sheet material is equal to or less than a sheet thickness of the second sheet material , the first sheet material and the second sheet material are overlapped with each other, the first joint line portion , the second joint line portion , and the third joint line portion each join the first sheet material and the second sheet material at an interface between the first sheet material and the second sheet material , the first joint line portion includes an A portion whose shortest in-plane distance from the second joint line portion is 20 times or more and 120 times or less the sheet thickness of the first sheet material , the second joint line portion includes a B portion whose shortest in-plane distance from the first joint line portion is 20 times or more and 120 times or less the sheet thickness of the first sheet material , the third joint line portion is in a first region interposed between the A portion and the B portion , a length of a length component of the third joint line portion in the first region in an extension direction of an intermediate line between the first joint line portion and the second joint line portion is 250 mm or more, and characterized in that at least one of the first j oint line portion or the second joint line portion is a curved line and the third joint line portion between the first joint line portion and the second joint line portion is also a curved line. <EOS>