An electric motor driving apparatus controls driving of an electric motor having two or more phase windings whose ends are open by using first and second inverters. A control unit includes a first inverter control circuit and a second inverter control circuit. The first inverter control circuit generates a first voltage command as an output voltage command to the first inverter based on a torque command. The second inverter control circuit generates a second voltage command as an output voltage command to the second inverter. The control unit determines a composite voltage command based on a first voltage command vector and a second voltage command including a case, in which a pure phase difference between the first voltage command vector on a dq coordinate corresponding to the first voltage command and the second voltage command vector on the dq coordinate corresponding to the second voltage command is other than 180°.