A starting system rotates and starts an internal combustion engine by injecting fuel into a predetermined cylinder using an injector and igniting the fuel using an ignition plug, and upon starting the engine, the fuel pressure supplied to the injector is detected, and the engine is started by combustion in the predetermined cylinder only when the detected pressure is at or greater than the predetermined pressure, thereby guaranteeing the fuel pressure when combustion starting is employed, and consequently the engine can be securely started. In operation, the present starting system rotates and starts the engine by injecting the fuel into a predetermined cylinder using the injector and igniting the fuel using the ignition plug, and upon starting the engine, the fuel pressure supplied to the injector is detected, and the engine is started by combustion in the predetermined cylinder only when the detected pressure is at or greater than the predetermined pressure, thereby guaranteeing the fuel pressure when combustion starting is employed, and consequently the engine can be securely started.