To suppress an amount of unburned HC at the time of low load operation and reduce an amount of smoke generated at the time of high load operation by forming a main injection hole and an auxiliary injection hole in a nozzle body of a fuel injection nozzle and forming a groove which is apart from the auxiliary injection hole in the peripheral direction and is extended from below a seat part to a main injection hole side.

A fuel injection nozzle 10 is provided in such a manner that a tip of a nozzle part 11 faces a combustion chamber, and the nozzle part 11 is such that a needle valve 14 is stored in a nozzle body 13. A seat part 22 is formed in the nozzle body 13, and fuel injection is stopped when a valve seat 23 of the needle valve 14 is seated on the seat part 22. Moreover, a main injection hole 17 is formed below a hole part 25 of the nozzle body 13 along the nozzle center C, and a plurality of auxiliary injection holes 27 are formed on and pass through a tapered surface 24 radially centered on the nozzle center C. Furthermore, a fanlike groove 28 having a predetermined depth is provided on the tapered surface 26 between the auxiliary injection holes 27, and each groove 28 is provided in such a manner that it is communicated with the main injection hole 17 through the hole part 25.