Abstract: A needle assembly 1 includes a hub 4 retaining a cannula 3, a protective unit 5 advancing and retracting to surround the forward end of the cannula 3, and a cylindrical portion 6 surrounding the outer periphery of the protective unit 5; the protective unit 5 has a construction in which a protective cover 7 protruding from and retracting into the cylindrical portion 6 is formed integrally with a spring portion 8 so as to be in series therewith, with the hub 4 and the cylindrical portion 6 being coupled together to form a hub member.

Abstract: A needle assembly 1 includes a hub 4 retaining a cannula 3, a protective unit 5 advancing and retracting to surround the forward end of the cannula 3, and a cylindrical portion 6 surrounding the outer periphery of the protective unit 5; the protective unit 5 has a construction in which a protective cover 7 protruding from and retracting into the cylindrical portion 6 is formed integrally with a spring portion 8 so as to be in series therewith, with the hub 4 and the cylindrical portion 6 being coupled together to form a hub member. Further, the protective cover 7 is provided with an engagement protrusion 24, and the hub member is provided with a guide means G; when the protective cover 7 is retracted from a pre-use state (FIG. 4(a)) in which it is situated at an advanced position, the engagement protrusion 24 moves backwards while rotating and in contact with an inclined surface 14a (FIG. 4(b)); when the protective cover 7 advances from a use state (FIG.