Abstract: A vein catheter placement assembly consisting essentially of a catheter unit and a puncture needle unit longitudinally slidably positioned in the catheter. The puncture needle unit comprises a hollow longitudinally grooved puncture needle, and a finger-grip attached to the end of the needle remote from the needle point; the finger-grip, which extends laterally at an angle to the needle plane and thereby facilitates proper insertion of the assembly into a vein, is hollow and made of transparent material, providing a visible receptacle for the reception of blood released upon puncture of a vein by the needle point. The catheter unit comprises a catheter and, communicating therewith and laterally extending therefrom, a tube adapted to be connected to an infusion liquid source.