Fuel injection nozzle for self-igniting internal combustion engines

A fuel injection nozzle for self-igniting internal combustion engines, having a nozzle body (10) with an elongated bore (12), one end of which is an injection end in which a conical valve seat face (14) is formed and from which face at least one injection port (20) extends, the injection nozzle including a valve needle (30) which opens counter, to the flow direction of the fuel, which valve needle (30) is guided displaceably in the end of the elongated bore (12) opposite the injection end, and which valve needle (30), on its end toward the valve seat face (14), has a closing cone (31) which cooperates with the valve seat face (14), characterized in that each of the at least one injection ports (20) have cross sections which, beginning at the valve seat face (14) decreases continuously as far as a smallest cross section (25), embodied at precisely one point, and from there on widens again continuously, so that a convergent part (21) of the injection port (20) and a divergent part (22) of the injection port (20) are separated from one another by the smallest cross section (25), wherein the smallest cross section is disposed between the center and the outer end (28) of the injection port (20).