The application discloses a catheter instrument (1000) comprising a needle tip shielding device (100), a catheter hub (200) and a needle unit (300), wherein the needle unit (300) is provided with connecting means (301) for connection to the catheter hub (200), and with connecting means (302) for connection to an external device. The needle tip shielding device (100) comprises a body with a rear side (106), a front side (107), a hole (102) extending from the rear side (106) to the front side (107), and a resilient arm (103) extending at an attachment point (105) from the front side (107) of the body; wherein the resilient arm (103) has a resting state from which it may be forced to yield free passage through the hole (102) in an axial direction of the body, the resilient arm (103) being adapted for clamping a needle tip (304) of a hollow needle (303) extending through the hole (102) in a direction from the rear side (106) to the front side (107), when being in the resting state.