A driving system includes a first alternating-current rotary electrical machine and a second alternating-current rotary electrical machine. The driving system includes: a first inverter electrically connected to the first alternating-current rotary electrical machine; a second inverter electrically connected to a first end of each of phase windings constituting the second alternating-current rotary electrical machine; a step-up converter; and a third inverter that is electrically connected to a second end of each of the phase windings and transfers power to a second direct-current power source different from the first direct-current power source to drive the second alternating-current rotary electrical machine. The step-up converter raises an output voltage of the first direct-current power source and outputs the output voltage to the first inverter and the second inverter. The second direct-current power source and the first alternating-current rotary electrical machine are connected by a single connection route.