Needle cluster

Abstract

The invention relates to a functioning inner needle assembly, Inner Needle Assembly (1) consisting of: a tubular outer needle (10); an outer needle holder (20) in which the base of the outer needle (10) is fixed; an inner needle (30) inserted into the outer needle (10) and the outer needle holder (20); The casing (50) holds the needle in (30) and keeps the detachable outer needle base (20) at one end of it, in which the casing (50) includes the clamping part (51) held by the user, and the extension part (53) is provided to extend from the clamping part (51) in the axial direction of the inner needle (30) and hold the outer needle base (20) at its end, the extension part (53) has, on the outer perimeter surface, a stopper (53d) that positions the outer needle base (20) in the axial direction of the inner needle (30), and the stopper (53d) is configured to protrude partially in the circumferential direction of the needle in (30) or is configured so that the amount of protrusion varies in the circumferential direction of the needle in (30),