The control apparatus is for an electric rotating machine which is mounted as an engine on a vehicle together with a power conversion circuit to be connected to the electric rotating machine, and a cooling apparatus for circulating coolant to the electric rotating machine and the power conversion circuit through a circulation channel, including. The control apparatus includes a limiting means for performing a limiting operation to limit an amount of electric power supply from the inverter to the electric rotating machine each time a circulation starting timing of the coolant comes, and a terminating means for terminating the limiting operation after a lapse of a predefined period from start of the limiting operation.