As for the detention needle assembly body, while possessing ahead the sharp needle in the point, while being locked to the basic end of the needle and the inside needle, in order the needle hub and the inside needle outside is locked to the basic end of the outside needle and the outside needle of the air which passes in the basic end or the side section of the needle hub and the outside needle hub, to communicate with the lumen of the outside needle, while it is provided in opening and the outside needle hub which are provided, the possible hole or the slit is formed the inside needle, at the same time, passing, the seal component which the hole or the slit blocks the occasion where removal leaving it does the needleIt was provided in the outside needle hub, passed through the inside needle to the outside needle when the needle and the outside needle inside the said operating the function part and the function part which it moves operates according to those longitudinal directions in state, it has possessed with the portable control expedient which it obstructs or controls the movement for the seal component of the inside needle.留置針組立体は、先端に鋭利な針先を有する内針と、内針の基端部に固定された内針ハブと、内針が挿通される中空の外針と、外針の基端部に固定された外針ハブと、外針ハブの基端部または側方部に、外針の内腔と連通するように設けられた開口と、外針ハブに設けられ、内針を挿通可能な孔またはスリットが形成され、かつ、挿通された内針を抜去した際に孔またはスリットが閉塞するシール部材と、外針ハブに設けられ、内針を外針に挿通した挿通状態で該内針および外針をそれらの長手方向に沿って移動操作する操作部と、操作部を操作したときの内針のシール部材に対する移動を阻止または抑制する移動抑制手段とを有している。
