To provide a manufacturing method of a rotary electric machine, the method being able to reduce a cogging torque more efficiently.

The method includes a step of measuring the cogging torque of a motor having a stator and a rotor and a step of processing the stator of the motor, in particular, any one among teeth 13, based on the measured data to reduce the cogging torque thereof. In addition, processing for a teeth 13 selected so as to reduce the cogging torque is performed, by adding a magnetic material 24 on a surface 23 thereof, with the surface facing the rotor.