A rotating electrical machine control system includes a frequency converting portion that is interposed between a rotating electrical machine for driving a vehicle and a DC power source for supplying electric power to the rotating electrical machine, and that converts an output of the DC power source to an AC output at least during powering operation of the rotating electrical machine; a voltage converting portion that is interposed between the DC power source and the frequency converting portion, and that boosts the output of the DC power source based on a boost command value which is set according to a target torque and a rotational speed of the rotating electrical machine; and a control portion for controlling the frequency converting portion and the voltage converting portion.