PROBLEM TO BE SOLVED: To provide a pre-filled syringe, wherein a seal member is surely separated from an external cylinder without being left at the distal end of the external cylinder when a seal cap is separated from the external cylinder.SOLUTION: The pre-filled syringe 1 includes a helical groove 34 which is formed on the inner surface of a collar 32 in the external cylinder 2. The seal cap 5 includes a helical projection 53, which has a width smaller than the width of the helical groove 34, on the outer surface of a nozzle storage part 51, and also internally stores the seal member 8 in a state of being compressed inward by a seal member holding part 54. In the syringe 1, the seal cap 5 is mounted on the nozzle 31 of the external cylinder, thereby allowing the nozzle 31 to be tightly sealed by pressure contact with the seal member 8. A gap is formed between the side part of a screwed helical groove and the side part of the screwed helical projection. The seal cap is rotated by prescribed angle in a state where movement is not performed in the axial direction of the external cylinder in an initial stage of the rotation of the seal cap in a screwing release direction.COPYRIGHT: (C)2010,JPO&INPIT【課題】シールキャップの外筒からの離脱時に、シール部材が外筒先端に残留することなく確実に外筒より離脱するプレフィルドシリンジを提供する。【解決手段】プレフィルドシリンジ１は、外筒２のカラー部３２の内面に形成された螺旋状溝部３４を備え、シールキャップ５は、ノズル部収納部５１の外面に螺旋状溝部３４の幅よりも狭い幅を有する螺旋状突出部５３を備え、内部にシール部材８をシール部材保持部５４をにより内側に圧縮された状態にて収納している。シリンジ１は、外筒のノズル部３１にシールキャップ５が装着され、ノズル部３１がシール部材８に圧接した密封状態となっており、かつ、螺合した螺旋状溝部の側部と螺旋状突出部の側部間には空隙が形成されており、シールキャップの螺合解除方向への回転時初期において、シールキャップは、外筒の軸方向に移動しない状態にて所定角度回転する。【選択図】図６
