Anxiety has profound influences on a wide range of cognitive processes, including action monitoring. Event-related brain potential (ERP) studies have shown that anxiety can boost early error detection mechanisms, as reflected by an enhanced error-related negativity (ERN) following errors in high-anxious, as compared with low-anxious, participants. This observation is consistent with the assumption of a gain control mechanism exerted by anxiety onto error-related brain responses within the dorsal anterior cingulate cortex (ACC). However, whether anxiety simply enhances or, rather, alters early error detection mechanisms remains unsolved. In this study, we compared the performance of low- versus high-trait-anxious participants during a go/no-go task while high-density EEG was recorded. The two groups showed comparable behavioral performance, although levels of state anxiety increased following the task for high-anxious participants only. ERP results confirmed that the ERN/Ne to errors was enhanced for high-anxious, relative to low-anxious, participants. However, complementary topographic analyses revealed that the scalp map of the ERN/Ne was not identical between the two groups, suggesting that anxiety did not merely increase early error detection mechanisms, but also led to a qualitative change in the early appraisal of errors. Inverse solution results confirmed a shift within the ACC for the localization of neural generators underlying the ERN/Ne scalp map in high-anxious participants, corroborating the assumption of an early effect of anxiety on early error-monitoring functions. These results shed new light on the dynamic interplay between anxiety and error-monitoring functions in the human brain.