NEEDLE ASSEMBLY

PROBLEM TO BE SOLVED: To provide a needle assembly which enables easy puncture without application of rotary torque when a protection cover moves from a state before use to a state of use.SOLUTION: A needle assembly 1 includes: a protection cover 4 which advances and retreats with respect to a hub 3 that holds a cannula 2; a tubular section 5 which is provided on the hub and houses the protection cover so as to be able to protrude and retract from the tip; a spring section 6 as a biasing means which is mounted elastically between the hub and the protection cover; an engagement protrusion 14 which is provided on one of either the tubular section or the protection cover; and a guide means 21 which is provided on the another of either the tubular section or the protection cover and regulates movements of the engagement protrusion. When the protection cover retreats from a state before use to a state of use, the guide means causes the engagement protrusion to move in an axial direction, and the protection cover retreats without rotating. Rotary torque is not generated during the use, and puncturing can be easily performed.