A cylinder tip (22) of a syringe barrel (18) of a pre-filled syringe (10) has a projection (30) formed to radially project from a outer periphery of a proximal end part of the cylinder tip (22), and a cap (14) has a cylindrical cover (50) that covers an outer periphery of the cylinder tip (22). A proximal-side inner periphery (50a) has a small distance part (50b) . A distance (L1) from a rotation axis (a1) of the cap (14) to the small distance part (50b) at the time when the cap (14) is threadedly engaged with the cylinder tip (22) is smaller than a distance (L2) from the rotation axis (a1) to an outer end of the projection (30).
