PROBLEM TO BE SOLVED: To provide a lancet of a novel structure in which a cap can be removed quickly even when it is twisted to any side in a circumferential direction, and to provide a puncture instrument using the same.SOLUTION: In a lancet 10, a hub covering a base end part of a puncture body 16 and a cap covering a distal end part of the puncture body 16 are formed, the puncture body 16 covered by the hub and the cap 20 is housed in a protector 14, and the hub is held by the protector 14. A first inclined plane 38 is provided at one side of the cap 20 and the protector 14, and a contact part 62, which is in contact with the first inclined plane 38 and applies a tensile force between the cap 20 and the hub by the rotation in any direction in a circumferential direction, is provided at the another side of the cap 20 and the protector 14.
