A needle safety device (12) for a medical device, in particular for an IV catheter assembly (10), being movably arranged on the needle (24) comprising: a first part (42) made of a suitable plastic material； a second part (44) preferably made of a strip of suitable metal sheet； and a ring (46) surrounding the said first part (42) and said second part (44) having elastic properties made of suitable elastomeric material. The invention also relates to an IV catheter assembly 10, comprising: a catheter housing (14) having a proximal section (26) and a distal section (28), wherein the proximal section (26) defines an enclosure (30) to retain therein the needle safety device (12) prior to use； wherein the said needle safety device (12) is removable from the enclosure (30) in the catheter housing (14) once the needle tip (36) is received in the needle safety device (12) upon withdrawal of the needle (24) from the catheter tube (16).
