A kind of cannula structures, it includes an outer tube and a puncture needles. Outer sleeve inner wall is convexly equipped with a ribs. Puncture needle wears what outer tube, and wherein one end of puncture needle has a needle tip, wherein one end of the convex dew what outer tube of needle tip. When puncture needle takes out Hou from outer tube, the inner space of outer tube is supported by ribs, and outer tube is avoided to deform and be crushed.一種插管結構，其包含一外套管及一穿刺針。外套管內壁凸設有一加強肋。穿刺針穿設於外套管，穿刺針的其中一端具有一針尖部，針尖部凸露於外套管的其中一端。當穿刺針自外套管內取出後，藉由加強肋以支撐外套管的內部空間，避免外套管變形而被壓扁。
