Electrical motor noise in hybrid electric vehicle (HEV) is in general expected that it has lower level in noise and vibration than conventional internal combustion engine does. In this paper, abnormal noise component, which may be annoying noise, of the traction motor occurred after an endurance vehicle test is investigated experimentally. The ±1 order of the number of slots is understood by a theoretical model, and the source of the abnormal noise is examined by cross-check investigation and is identified that it is caused by a failure of magnet fixing method. The improvement of the abnormal noise is confirmed by changing the fixing method from bond to mold.