Abstract: A leader 10 for fly fishing proposed herein is formed of a single monofilament line. The leader 10 for fly fishing includes a tippet section 11 to which a fly is tied, a butt section 12 to which a fly line is tied, and an intermediate section 13 provided between the tippet section 11 and the butt section 12. Herein, the butt section 12 is thicker than the tippet section 11. The intermediate section 13 includes a front tapered portion 13a having a thickness that gradually increases from the tippet section 11, a rear tapered portion 13b having a thickness that gradually increases from the butt section 12, and a thicker portion than the butt section 12.