A control apparatus for an internal combustion engine includes a crankshaft, a camshaft for actuating a valve of the engine, and a rotating electrical machine that is coupled to one of the crankshaft and the camshaft. The apparatus includes a computer that controls the rotating electrical machine. The rotating electrical machine includes a rotor and a plurality of rotation sensors, each of which outputs a signal corresponding to induced voltage generated by rotation of the rotor. The computer controls the rotating electrical machine based on the signals from the rotation sensors, and detects the occurrence of reverse rotation in the engine when an output pattern of the signals from the rotation sensors is different from an output pattern during forward rotation of the engine. As a result, the apparatus promptly detects the occurrence of reverse rotation of the internal combustion engine without providing additional sensors or rotors.