Patent ID: 7367517

Claim:
A fuel injection device comprising: a nozzle body formed with an injection hole for injecting fuel; and a nozzle needle reciprocating in the nozzle body to open and to close the injection hole, wherein the nozzle needle includes a sliding portion capable of moving in the nozzle body in a sliding manner, an insertion portion, of which diameter is smaller than that of the sliding portion, and a pressure receiving portion connecting the sliding portion with the insertion portion, the nozzle body includes a guide portion for slidably holding the sliding portion and a fuel sump chamber formed on the injection hole side of the guide portion so that the insertion portion is inserted through the fuel sump chamber, the guide portion and the sliding portion provide a clearance therebetween so that the clearance decreases toward the fuel sump chamber, and the sliding portion is formed on an outer periphery of the nozzle needle so that a diameter of the outer periphery thereof enlarges toward the pressure receiving portion.