A medical needle device 71 comprises: a hub 10 having an injection needle 11 and a tube 40 respectively fixed at a top end and a rear end thereof a substantially cylindrical sheath 80 which has a wing 51 mounted thereon and supports the hub 10 in an interior side thereof and a protector 82 fit on the sheath 80 where the sheath 80 is slidable back and forth from a puncturing position to a storing position, wherein: the protector 82 comprises: a circular front part 82a a circular rear part 82b and connecting parts 86 connecting the front part 82a and the rear part 82b, which have spaces for protruding a pair of wings 51, 52 on the sheath 80 therefrom for enabling slide of the sheath 80 and an outer peripheral surface of the sheath 80 and a front side and a rear side of the protector 82 form a position controlling mechanism 81, 85 for positioning and fixing the sheath 80 relative to the protector 82 on the puncturing position and the storing position.
