To provide an indwelling needle assembly in which the timing of closing a sealing member corresponding to a hemostasis valve is made easy to understand when filling blood so as to remove air in a pusher.SOLUTION: The indwelling needle assembly 1 includes an inner needle 11, an inner needle hub 12, an outer needle 15, a cylindrical outer needle hub 16, and a distal side region and a proximal side region A sealing member 17 arranged so as to seal the space therebetween, a tube which is disposed in the outer needle hub and is movable between a closed position and an open position where the closed position is pushed open by the sealing member Shaped pusher 18 and a tubular actuating member 4 abutting the proximal end face of the pusher and operated to push the pusher to move it to the open position, wherein the outer needle hub comprises at least a pusher Wherein at least one of the pusher and the actuating member has transparency so that the inside can be visually recognized and the pusher and the actuating member are disposed proximal to the pusher The inner holes communicate with each other at the side end face and are configured to be able to distinguish the proximal end face of the pusher.BACKGROUND OF THE INVENTION【課題】押し子内の空気を除去すべく血液を満たす際に、止血弁に対応する封止部材を閉じるタイミングを分かりやすくした留置針組立体を提供する。【解決手段】留置針組立体1は、内針11と、内針ハブ12と、外針15と、筒状の外針ハブ16と、外針ハブ内を遠位側領域と近位側領域とに分けてそれらの間を封止するように配置される封止部材17と、外針ハブに内に配置され且つ閉位置と封止部材を押し開く開位置との間で移動可能な筒状の押し子18と、押し子の近位側端面に当接し且つ押し子を押して開位置へと移動させるべく操作される筒状の作動部材4とを備え、外針ハブは、少なくとも押し子の近位側端面を覆う部位が透明性を有し、押し子及び作動部材のうち少なくとも一方は、中が視認できるように透明性を有し、押し子及び作動部材は、押し子の近位側端面においてそれらの内孔が互いに連通し、且つ押し子の近位側端面を識別できるように構成されている。【選択図】図1
