To provide a new puncture needle with a needle tip which sinks in an outer member when the puncture needle is removed from a puncture auxiliary device after it is used once and never protrudes again.

The puncture needle 1 is equipped with a slider 3 on which a needle 2 is fixed and the outer member 7 which accommodates the slider 3 in the inner cavity in a manner that the slider 3 moves in the axial direction and has a connecting part 6 to a needle tip outlet 4 at the front end and a connecting part 6 to the puncture auxiliary device 5 at the rear end, and the slider 3 has a guard part 8 slidingly coming into contact with the inner cavity of the outer member 7 at a site where the needle tip makes slanting movements. As a result, if the puncture needle 1 is removed from the puncture auxiliary device 5 after being used for collecting a specimen by connecting the puncture needle 1 to the puncture auxiliary device 5, the slider 3 tilts downward with the needle tip side in a natural state, and the needle tip 2a never protrudes from the needle tip outlet 4 because of the needle tip 2a abutting on the peripheral part 9 of the needle tip outlet 4. Consequently, the hygienic problems and the risk of blood-borne infections are reliably eliminated.