A puncture needle cartridge (2) comprises: a columnar lancet body (6) having a puncture needle on the front end side and a puncture instrument mount (5) on the rear end side a protective cap (13) covering the puncture needle and having a shape extending toward the front end a skin contact part (10) placed in front of the tip of the puncture needle, having a planar shape perpendicular to the puncture needle, and formed with a through hole to put the protective cap (13) through an elongate plate-like extension (9) extending from the skin contact part (10) toward the rear end and an elastic object (8) for coupling the extension (9) to the lancet body (6) and making the tip of the puncture needle be biased to be located in the rear end side behind the skin contact part (10).
