<p>Mind wandering in the workplace often causes work errors and may trigger accidents, but there is a lack of clarity about the effects of working memory capacity on the neural mechanisms of mind wandering in drilling crews. Therefore, to determine the effects of different working memory capacities on mind wandering and to explore the neural mechanisms behind these effects, the present study was conducted with drilling crews from an actual drilling site. Participants were grouped based on their performance on the N-back task, and EEG data were collected during the SART task. The behavioral results showed that there were no significant differences in response time and accuracy between groups with different working memory capacities. The EEG results showed that the P3 amplitude during mind wandering was significantly larger in the group with high working memory capacity than in the group with low working memory capacity. Furthermore, there were significant differences in δ, θ, and α-band oscillatory power between the groups with high and low working memory capacities, suggesting the effects of attentional allocation of resources and executive control functions on mind wandering. These results highlight the influence of different working memory capacities on the neural mechanisms of mind wandering. The findings of this study offer novel evidence regarding the role of working memory capacity in the neural mechanisms underlying mind wandering and are expected to inform the development of vocational training programs and cognitive intervention strategies in the future.</p>