A control device has a predicting unit for predicting a first current flowing through a motor in a next control period, at a predicting time during a predetermined period after a change of switching state in an inverter by using a current detected before the change and for predicting a second current of a control period later than the next control period by one control period by using the predicted first current, a determining unit for determining a next operating state of the inverter by using the predicted second current and an instructed value so as to reduce a change of switching state in the change of the operating state, and a control unit for controlling the inverter to be set in the determined operating state in the next control period and controlling the current of the motor depending on the operating state of the inverter.