Control system of internal combustion engine

An object of the present invention is to provide a control system of an internal combustion engine 1 capable of, in a case where fuel is injected from an injector for a plurality of times in a divided manner based on an operation status of the internal combustion engine 1, controlling an injection quantity of the injector accurately against influence of a variation of an injection quantity of the injector on an air-fuel ratio accuracy, while preventing performance deterioration of the internal combustion engine 1 caused by multiple-times injection of fuel. An internal combustion engine control system according to the present invention is a control system of an internal combustion engine 1 including an injector 5 for making a valve operate and inject fuel by applying an excitation current to a coil and injecting fuel into a combustion chamber 21 directly in a manner dividing into a plurality of times of fuel injection, the internal combustion engine control system including means for learning invalid pulse width and valid pulse width of the injector based on the number of times of fuel injection of the internal combustion engine 1.