To provide a correction method of resolver correction device and resolver correction device that can reduce rotation angle (the rotation speed) detection error caused by resolver. An excitation signal supply circuit supplies an excitation signal of an excitation frequency to the resolver during a normal operation, for supplying the excitation signals of a plurality of frequencies including the excitation frequency to the first phase shifter or the second phase shifter during a calibration operation. A shift amount searching circuit searches the first shift amount setting value for each frequency of the excitation signal such that the first shift amount becomes 45 degrees, and the second shift amount setting value for each frequency of the excitation signal such that the second shift amount becomes 135 degrees, while referring to the detection result of the phase difference detection circuit during the calibration operation, and stores in the correction table.