We recorded the auditory evoked magnetic fields from children with and without absolute pitch under the following conditions: (a) hearing 1000 Hz pure tones inattentively, (b) hearing eight random tones inattentively and (c) listening to eight random tones and identifying each tone. We calculated the appearance rate of N100m as the ratio of the subjects who had N100m. There was a significant positive correlation between the appearance rate of N100m and age in both groups. There was also a significant positive correlation between the appearance rate of N100m and the kinds of the task only in children without absolute pitch. These results suggest that, in the children with absolute pitch, N100m was elicited equally in every session because of their automatically driven auditory attention. No significant correlation was found between the appearance rate of N100m and the possession of absolute pitch.