A jet injector (10.86), comprising: a pre-filled syringe (18.88) 5 comprising: a receptacle part (20) defining a fluid chamber (22,106) containing a fluid medicament； an injection assistance needle (24) disposed at a distal end of the fluid chamber (22,106), which has an injection tip (26) configured to pierce an insertion site, and which defines a fluid path in communication fluid with the fluid chamber to inject the fluid medicine from the fluid chamber (22, 106) into an injection site； a piston (28,104) movable within the fluid chamber (22,106)； and a housing (12,108) that houses the pre-filled syringe (18,88) and is configured to allow the insertion of the injection assistance needle (24) at the insertion site at an insertion point that is at a depth of penetration under a surface at the insertion site； a syringe holder (16) that fixes, supporting, the pre-filled syringe (18.88) to the housing (12,108)； and a power source configured to push the plunger (28,104) with a force selected to produce an injection pressure in the fluid chamber fluid medicine (22,106) that remains substantially at about 5.5 bar (80 psi) and 68.9 bar (1000 psi) during the injection of the fluid medication to inject the fluid medication from the fluid chamber through the injection assist needle (24) to the injection site, characterized in that the pre-filled syringe (18, 88) further comprises a syringe body (36,120) which includes a tongue (34) and a wall (30) and a needle connector part (32) of integral construction, and the injection assist needle (24) is mounted in the needle connector part (32).Un inyector de chorro (10,86), que comprende: una jeringa precargada (18,88) 5 que comprende: una parte de receptáculo (20) que define una cámara de fluido (22,106) que contiene un medicamento fluido； una aguja de asistencia a la inyección (24) dispuesta en un extremo distal de la cámara de fluido (22,106), que tiene una punta de inyección (26) configurada para perforar un lugar de inserción, y
