PROBLEM TO BE SOLVED: To provide a puncture instrument capable of surely mounting a protector for covering an outer needle hub without any increase in size even when the outer needle hub for holding an outer needle is provided with a branch tube and a blade, and protecting the outer needle and an inner needle projected from the outer needle to prevent positional shifting thereof.SOLUTION: A protector 5 includes: a cylindrical part 51 for storing an outer needle 21 and a support leg part 52 axially extended from the cylindrical part to form the side surface of the protector and form an opening 53 on the side surface. One end of an inner needle hub 41 is provided with a fitting part 41a cylindrically formed along the circumferential direction of the inner needle hub, and one end of the support leg part is provided with a groove part 52a formed to curve along the circumferential direction of the fitting part and have predetermined length and width. Projection parts 22A, 22B of an outer needle hub 22 are disposed in the opening of the side surface of the protector, a part of the fitting part is fit in the groove part of the support leg part, and the outer needle is stored in the cylindrical part.
