PROBLEM TO BE SOLVED: To perform a safe and secure procedure by more securely and accurately confirming the position of an indwelling needle tapped into a patient.SOLUTION: The indwelling needle 10 comprises a catheter 12, an outer needle hub 14 for holding the catheter 12, a puncture needle 16 to be inserted into the catheter 12, and an inner needle hub 18 for holding the puncture needle 16. The catheter 12 has a detection part 30 composed of a long body 28 wound around the outer surface of an inner tube 26 in an outer needle body 24. The detection part 30 is formed in a prescribed length along the axial direction of the inner tube 26. The outer surface of the detection part 30 has continuous projections and recesses to project toward the outer periphery, and a space 34 in which air is enclosed is formed inside the detection part 30.COPYRIGHT: (C)2010,JPO&INPIT【課題】患者に穿刺された留置針の位置をより一層確実且つ高精度に確認し、安全且つ確実な手技を行う。【解決手段】留置針10は、カテーテル12と、カテーテル12を保持する外針ハブ14と、カテーテル12の内部に挿通される穿刺針16と、穿刺針16を保持する内針ハブ18とを備え、カテーテル12は、内管26の外周面に巻回された長尺体28からなる検出部30を外針本体24に有する。この検出部30は、内管26の軸線方向に沿って所定長さで形成され、その外周面が外周側に向かって凸状となるように連続的な凹凸形状となり、その内部には空気の封入された空間部34が形成される。【選択図】図3