In a starting system of an internal combustion engine including a fuel injection valve that directly injects fuel into a corresponding cylinder and a spark plug that ignites an air-fuel mixture in the cylinder, injection of the fuel from the fuel injection valve and ignition performed by the spark plug are stopped when engine stop conditions are met. If the engine restart conditions are met during rotation of the engine after the engine stop conditions are met, the fuel is injected from the fuel injection valve into an expansion-stroke cylinder that is in the expansion stroke at the time when the engine restart conditions are met, and the mixture formed in the expansion-stroke cylinder is ignited by the spark plug.