There is provided a syringe capable of preventing the occurrence of "link-thread" from the distal end nozzle when the cap is pulled out, even in the case where the medicinal liquid filled has a high viscosity. The inner peripheral surface (631) of the seal cap (63) in the cap (6) is brought into close contact with the outer peripheral surface (214) of the distal end side portion of the distal end nozzle (21) in the barrel (2) so that the distal end opening (211) is hermetically closed off. At the same time, the outer peripheral side of the luer lock adapter (22) is covered with the outer tubular cover (62) of the cap. The bulge part (213) is formed in the distal end side portion of the inner aperture (212) in the distal end nozzle so that the aperture diameter ( d ) of the distal end opening is reduced to a small aperture diameter and, in addition, the length of seal (s) by the seal cap (63) is made to be a relatively short, predetermined length. The diameter of the filled medicinal liquid to be sucked in until the vacuum breaks down when the cap is pulled out, is made very small and, in addition, the vacuum is made to break down instantly, thereby making it possible to prevent the occurrence of "link-thread" even if the medicinal liquid filled is of high viscosity.本發明提供一種注射器，該注射器即使填充藥液為高黏度，亦可避免在拔出蓋時自前端噴嘴產生牽絲。前述注射器係使蓋(6)之密封蓋(63)之內周面(631)緊貼於筒(2)之前端噴嘴(21)之前端側部分的外周面(214)，而密封前端開口(211)。同時利用蓋之外筒罩部(62)包覆魯爾鎖部(Luerlock)(22)之外周側。在前端噴嘴之內孔(212)之前端側部分設置膨出部(213)而使前端開口之孔徑(d)成為細孔，且使密封蓋(63)之密封長度(s)成為較短之特定長度。在拔出蓋時，直至真空受到破壞為止使所吸引之填充藥液之直徑成為微小直徑，且使真空立刻破壞，以使得即使係高黏度之填充藥液亦不產生牽絲。
