Identifying the relationship between workload content and health complaints would likely aid the establishment of preventative health care strategies. The study population consisted of 137 male workers from a pharmaceutical company. The workloads of the target subjects were divided into three groups (A, B, and C+D) according to the scores of a self-administered questionnaire. The results of General Health Questionnaire (GHQ, 12 items version) for assessing health complaints were also analyzed. The percentages of workers who reported feelings of stress in response to overtime work, irregular work, business trips, nighttime work, no rest and/or no nap, mental workload, and physical workload were 22.6%, 15.3%, 2.9%, 8.0%, 13.9%, 58.3%, and 18.2%, respectively. The significant odds ratio of workload predicting health complaints was 6.9 for subjects in group B and 13.9 for subjects in group C+D. Among them, the significant odds ratios of mental workload predicting health complaints and a positive GHQ were 5.7 and 4.0, respectively. Having no regular exercise also resulted in ORs of greater than 3 for health complaints and a positive GHQ. To cope with the health complaints of workers, mental health support by reducing individual workloads is recommended.