PREFILLED SYRINGE

PURPOSE:To prevent alteration or contamination of a medical fluid by downward sliding a pressing-down member after it is fixed in a crowned shape to a tip member, engaging an engaging claw with a medical fluid delivery port by deforming a skirt inside, and airtightly installing the tip member on the medical fluid delivery port of a syringe outer cylinder. CONSTITUTION:Packing 4 is installed in a medical fluid deriving part of a tip member 2, and after rubber packing 5 is installed in an injection needle installing part, a pressing-down member 3 is lightly fixed in a crowned shape, and when it is downward pushed by applying it to a medical fluid delivery port 11 of a syringe outer cylinder 1, the tip member 2 downward moves along the medical fluid delivery port 11, and the packing 4 is inserted into and fixed to the medical fluid delivery port 11. When a downward movement of the tip member 2 stops, the pressing-down member 3 downward slides along a skirt outer wall of the tip member 2, and deforms a skirt inside, and firmly enages an engaging claw 24 with the medical fluid delivery port 11. When the pressing- down member 3 downward moves, the engaging claw 35 engages with a locking means 222 on the lower end of the tip member 2, and is firmly installed on the medical fluid delivery port 11 of the syringe outer cylinder 1.