An internal combustion engine has a variable valve timing apparatus including a driving motor between a crankshaft and a camshaft. The driving motor rotates synchronously with the camshaft when the valve timing apparatus is not in operation. A motor rotation sensor produces a motor rotation signal. When the engine rotation speed is below a reference speed, the driving motor is not energized. Under this condition, the rotation speed and the rotation direction of the engine are calculated based on the motor rotation signal in place of a crank rotation signal produced by a crank angle sensor. Further, the rotation stop position of the engine is calculated based on the motor rotation signal when the engine is stopped.