A 0-axis current calculator 7 configured to calculate a target value of the 0-axis current by setting the current of the open phase to be zero when one of the phases becomes open, or determines that the target value of the 0-axis current is zero when there is no open phase is provided. Based on the target values of the d-axis current and the q-axis current, the target value of the 0-axis current calculated by the 0-axis current calculator 7, and the d-axis current, the q-axis current, and the 0-axis current transformed by the d-q-0 transformer 8, the current supplied to each phase of the motor are controlled.