A puncture needle cartridge including a puncture needle, a lancet body adapted to cover part or all of a tip of the puncture needle, a cylindrical puncture needle holder disposed on an outer surface of the lancet body to permit the lancet body to move in an axial direction of the puncture needle and a protective cap that is separable from the puncture needle holder. The protective cap includes a base adapted to cover an opening in the puncture needle holder, a shaft protruding from the base, and arms mounted on the shaft and configured to abut an inner circumferential surface of the opening in the puncture needle holder by spreading in the opening. A space between tips of the arms is larger than an inside diameter of the opening in the puncture needle holder, and is reduced by elastic deformation when the arms are housed in the opening.
