We recorded the auditory evoked magnetic fields from adults with and without absolute pitch under the following conditions: hearing 1000 Hz pure tones inattentively (single tone session) and listening to eight random tones and identifying each tone (labeling session). In the adults with absolute pitch, the bilateral N100m dipole moments increased significantly in the labeling session. While, in the adults without absolute pitch, the left N100m dipole moment alone increased in the labeling session. These results suggest that the adults with absolute pitch execute the labeling task in the bilateral auditory cortices with interhemispheric cooperation, which does not operate in the adults without absolute pitch.