In addition to material rewards (such as money, food, and liquid), various social signals, including facial attractiveness, are perceived as incentives. Although material and monetary rewards are known to enhance various aspects of cognitive performance, it is not clear whether and how social signals affect cognition. The present study focused on facial attractiveness and investigated its effects on working memory. In addition, we used near-infrared spectroscopy (NIRS) to characterize the activation in the dorsolateral prefrontal cortex (DLPFC), an area known to be involved in the processing of reward-related cues in working memory. Our results show that compared to the non-reward condition, the cue for attractive faces enhanced working memory performance, but DLPFC activation did not differ between these two conditions. These results provide new evidence that facial attractiveness enhances verbal working memory performance and function via neural mechanisms different from those characterized for other types of rewarding cues.