stop control means and for starting an internal combustion engine

When a crank angle is controlled to stop at a stop position optimal crank angle through an automatic engine stop control of, such as a stop from the idle, or when the position crank angle stop can be estimated with high accuracy, the automatic restart of the engine is executed with an electric generator-motor (3) serving as an electrical motor or electrical generator, the next restart of the engine (2) . In contrast, when the crank angle is not controlled to stop at the stop position optimal crank angle, when the stop position of the crank angle can not be estimated with high precision, or when the stop position of the crank angle changes after the stop command, the motor is restarted by a DC starter motor (1) having an output torque greater than that of the electrically motor generator (3), the next engine restart.