An ECU independently controls power supply to two winding systems in a motor on a per-winding-system basis based on current command values each calculated for a corresponding winding system in accordance with a target assist torque. When a first winding system fails, the ECU transitions from a first state in which the ECU causes the winding groups of the two winding systems to produce the target assist torque to a second state in which the ECU causes the winding group of the other normal winding system to produce the target assist torque. If the current command value for the normal winding system is equal to or below a current threshold value that is set with reference to zero or a value close to zero when the failed winding system recovers to its normal state in the second state, the ECU transitions from the second state to the first state.