Fuel injection system for internal combustion engine

This fuel injection system includes a port injector (20), an in-cylinder injector (30), and a control device (50). The control device (50) sets the number of executions of maximum partial lift injection per injection stroke based on the pressure of a fuel supplied to the in-cylinder injector (30) and within a range of the number of injections in which an injection amount of the maximum partial lift injection per injection stroke becomes equal to or less than a target amount. This control device (50) allows the in-cylinder injector (30) to execute the number of executions of the maximum partial lift injection and allows the port injector (20) to inject the fuel by the amount equal to the shortfall compared to the target amount only in the maximum partial lift injection by the in-cylinder injector (30).