PURPOSE: To prevent preignition without deteriorating exhaust gas emission of a fuel injection device of an internal combustion engine.

CONSTITUTION: A fuel injection device is provided with a fuel injection valve 5 arranged on an intake passage 3, and wherein its fuel injection finishing timing is set to the time before an intake valve 4 is opened and its fuel injection direction is oriented toward an ignition plug 2 in a cylinder 1, a preignition generation detecting means 11 for detecting generation of preignition, and a fuel injection timing changing means 10 for delaying the fuel injection finishing timing of the fuel injection valve 5 to the time after the intake valve 4 is opened when the generation of preignition is detected by the preignition generation detecting means 11.