In contrast to previous research on work engagement that mainly focused on positive effects, this study, based on the perspective of interpersonal trust and conservation of resources theory, explores the process of possible negative impacts of work engagement on employees' physical and mental aspects. Sampling from 140 employees working for a quick-cutting chain company in Taiwan at three times points. The results show that work engagement has a positive relationship with job demands, and increased job demands lead to higher emotional exhaustion; in addition, the moderation of job control on the indirect effect of work engagement through job demands on emotional exhaustion was evident only when job control was low. Accordingly, based on the findings, theoretical and practical implications are discussed.