A fuel injection system designed to determine a correction value for correcting the quantity of fuel sprayed from a fuel injector into an internal combustion engine. The fuel injection system instructs the fuel injector to inject the fuel into the engine a plurality of times cyclically to learn an injection characteristic unique to the fuel injector and changes an injection duration for which the fuel is to be sprayed in each of injection events to disperse the injection durations evenly around a target injection quantity, thereby enabling the correction value to be determined in a decreased number of injections of fuel for a decreased amount of time.