Abstract: Mold nozzle for injecting plastic material, constituted by a cylindrical body forming sleeve, associated with a heating device and integrated in a receiving housing provided in the thickness of a mold. The nozzle opens out via a downstream orifice in the interior of the mold and is adapted to receive via its upstream orifice, opposite the preceding one, the flux of material injected from the molding machine nozzle. The mold nozzle is constituted by a first fixed cylindrical sleeve (3), which is immobilized on the wall of the mold and acts as the upstream orifice for the admission of the material. The nozzle has a second mobile sleeve (4), colinear with respect to the first sleeve, and mounted to slide telescopically inside of the first sleeve. The end (5) of the second sleeve, opposite of the end engaged in the first sleeve, comes into abutment against the wall (9) of the receiving housing (8) provided in the thickness of the mold (2).