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