A female syringe barrel (30) has two protrusions (42) provided on a cylindrical portion (38). A length (Lp) of the protrusion (42) along a direction, perpendicular to an axis of the cylindrical portion (38) and perpendicular to a direction in which the protrusion (42) protrudes from the cylindrical portion (38), is 2.0 to 4.5 mm. A width (W) of the protrusion (42) along an axial direction of the cylindrical portion (38) is 1.0 to 2.1 mm. Each of the two protrusions (42) has an inclined surface (42a), which opposes a trailing flank of the screw (28) when the two protrusions (42) are screwed into the screw (28) of the lock adapter (26), in an end portion close to the barrel body (36).
