The present invention relates to a brushless motor, and an objective of the present invention is to provide a brushless motor which can significantly reduce the cogging torque and torque ripple of the motor by minimizing the rate of change of magnetoresistance in accordance with a change in position of a rotor through the optimization of the shape design of the rotor and a stator, and can also reduce the weight of the brushless motor through the optimization of the shape design taking into consideration the materials of the rotor and the stator.