During start-up of an in-cylinder fuel injection spark ignition engine (1), an engine controller (21) calculates a start-up fuel injection pulse width TIST on the basis of a cooling water temperature Tw, an engine rotation speed Ne, and a fuel supply pressure Pf to a fuel injector (8) (S1). When the fuel supply pressure Pf exceeds a required fuel pressure, the engine controller (21) executes stratified combustion by means of compression stroke fuel injection. By setting the required fuel pressure precisely in accordance with a start-up condition defined by the start-up fuel injection pulse width TIST and the engine rotation speed Ne, the opportunities for stratified combustion during start-up increase, and the amount of hydrocarbon discharge decreases.