An internal combustion engine (1) causes an air/fuel mixture in a cylinder to combust due to ignition by a spark plug (14). The engine controller (50) calculates a temperature and pressure in the cylinder on the basis of the operating state of the engine (1) (531), calculates a limit ignition timing at which knock is not generated, on the basis of the temperature and pressure in the cylinder (54), and controls an ignition timing of the spark plug (14) to the limit ignition timing at which knock is not generated (55). Therefore, suitable control of the ignition timing is achieved, by means of a small number of adaptation steps.