FUEL INJECTION NOZZLE

PURPOSE: To secure the desired fuel flow in a unit time and reduce the capacity of a sack hole at the same time. CONSTITUTION: A protruded conical coupling section 16 is provided at the bottom section of the sack hole 13 of a hole type fuel injection nozzle 1 formed with multiple nozzle holes 15 at the round top section 14 of the tip of a nozzle body 5, and a recessed conical coupled section 26 to be coupled with the coupling section 16 at a prescribed clearance is provided at the tip of a needle 6 slidably stored in the inner hole 11 of the nozzle body 5. When the needle 6 is lifted from the truncated cone seat section 12 of the nozzle body 5, the flow of the fuel flowing from the truncated cone seat section 12 to multiple nozzle holes 15 via the sack hole 13 is made smooth. When the needle 6 is seated on the truncated cone seat section 12 of the nozzle body 5, the coupling section 16 and the coupled section 26 are brought nearby, and the capacity of the sack hole 13 can be reduced.