An electronic control apparatus configured to control electric power steering and provided integrally with an electric motor is electrically connected to an ignition switch and which assists a rotation operation of a steering column by rotation of the electric motor. A first magnetism detecting element configured to operate using power supplied via the ignition switch to output a first set of rotation angle signals of the electric motor. A second magnetism detecting element configured to operate continuously using continuously supplied power to output a second set of rotation angle signals of the electric motor. A controller configured or programmed to generate rotation angle information about the electric motor based on the first set of rotation angle signals and the second set of rotation angle signals outputted while the ignition switch is stopped and to calculate a position of a steering wheel from the generated rotation angle information.