This study examined the basis for introducing an ignoring task during cortical evoked response audiometry (CERA) using the N1-P2 response. Healthy hearing participants were assigned to two groups with and without an ignoring task (ignoring and listening groups) during CERA whose outcomes were compared with the pure-tone audiometry (PTA) in response to tone frequencies at 500-4000 Hz. The ignoring but not the listening group exhibited positive correlations between the PTA and CERA thresholds, and further showed negative correlations between the PTA threshold and the N1-P2 amplitude as the tone intensity decreased particularly for lower tone frequencies. Within the healthy hearing levels at least, conducting an ignoring task is thus considered to improve the validity of CERA for lower tone frequencies.