The vehicle-use tandem electric rotating machine includes a first stator-rotor pair, a second stator-rotor pair, and a controller individually controlling a first field current flowing into a first field coil of the first stator-rotor pair and a second field current flowing into a second field coil of the second stator-rotor pair. The first stator-rotor pair is configured to generate electric power to be supplied to essential electric loads, and the second stator-rotor pair is configured to generate electric power to be supplied to non-essential electric loads. The controller is configured to restrict the second field current from flowing into the second field coil when rotational speed of a vehicle engine driving the tandem electric rotating machine is lower than a predetermined threshold speed set above an idle speed of the vehicle engine.