The present invention relates to a type of medical instrument, in particular a fifth generation FSN needle, being a special tool for Fu's subcutaneous needling (FSN), comprising a needle handle, a needle core, a soft casing pipe and its handle, and a protective sleeve. The needle core is fixed on top part of the needle handle and consists of a needle core body and a needle core tip. On top part of the needle handle, a round_hole-type groove is provided. On this groove, a positioning notch is provided, including first longitudinal position point, and inlet and second longitudinal position point at two sides of the first longitudinal position point. The soft casing pipe handle is a round tube that can be inserted into said groove. On the soft casing pipe handle, a first bulge and second bulges are provided: the first bulge is used to fix the soft casing pipe and its handle； the second bulges are used to prompt sweep position.
