Abstract: A dual chamber prefillable syringe (100) includes: a cylinder (10) which has a bypass portion (11); a hub luer-lock (20); a front stopper (30); a middle stopper (40) which seals a preparation (S) together with the front stopper (30); an end stopper (50) which seals a solvent (L) together with the middle stopper (40); a finger grip (60); and a plunger rod (70) which is connected to the end stopper from the rear end side. A female screw portion (64) which is screwed around the axis line is formed on an inner circumferential surface of the finger grip (60), and a male screw portion (73) which is able to be screwed to the female screw portion is formed on an outer circumferential surface of the plunger rod (70).

Abstract: A combined container-syringe includes: a cartridge; a needle hub having a base portion, a cylinder portion inside which a bypass chamber is formed, and a needle attachment portion inside which an introducing hole communicated with an injection needle is formed; a front stopper; a rear stopper; and a plunger rod connected to the rear stopper, in which: a bypass groove communicated with the introducing hole, and an annular groove connected to the bypass groove are formed on an inner circumferential surface of the bypass chamber; an air-bubble introducing groove is formed on an outer circumferential surface of the front stopper, the air-bubble introducing groove extending from a rear end surface of the front stopper toward a front end; and the air-bubble introducing groove and the annular groove are communicated with each other in a state where a part of the front stopper is disposed in the cartridge.

Abstract: A luer-lock type cylindrical tip of a syringe has a luer tip of which a center portion is fitted with an injection needle and a luer-lock portion which is disposed outside the luer tip with a gap therebetween and which has a lock screw disposed therein. The lock screw is formed as a trapezoid screw having a root diameter set to the range of 8.0 mm±0.1 mm, an inner diameter set to the range greater than or equal to 6.6 mm and smaller than 6.8 mm, and a pitch set to the range greater than 2.5 mm and smaller than or equal to 2.8 mm. Accordingly, it is possible to reliably prevent the injection needle from being loosened or pulled out in the handling process. It is also possible to easily replace the syringe needle with another one having different size at the time of use.