For obtaining a natural-looking hair without excessive volume compared with traditional hair extensions, there are provided a hair extension and manufacturing & attaching method of the same, comprising a linearly extending base member (200); a plurality of hair extension strands (300) to be provided longitudinally along the base member (200), each of the plurality of hair extension strands (300) including a knot part (310) being a knot formed on the base member (200) and a hair part (330) extending from the knot part (310); and a fixing part (400) to be fixed to a portion of the hair part (330) so as to be adjacent to the base member (200) for connecting the plurality of the hair extension strands (300) to the hair of a subject.