An angle calculator detects a rotation angle θa of a rotor. A three-phase/d-q axis converter outputs detected current id, iq on d-q coordinate axes by making a conversion, based on a corrected detection angle θc obtained by adding or subtracting an amount of detection deviation from a time point of current detection to or from the detection angle θa. A command current calculator calculates command current id*, iq* on the d-q coordinate axes based on a steering torque T and a speed S. A feedback controller calculates command voltages vd, vq on the d-q coordinate axes based on the command current id*, iq* and the detected current id, iq. A d-q axis/three-phase converter converts the command voltages vd, vq into three-phase command voltages, based on a corrected detection angle θb obtained by adding an amount of detection deviation from a time point when a motor is driven to the detection angle θa. The deviation can be eliminated by the command voltages, and the motor can be driven with high precision.