In order to clarify the characteristics of job stress in scientific researchers, a self-administered questionnaire survey for 16,330 workers was carried out at Tsukuba Research Park City, Japan. The data of 7,063 (43%) workers aged 20-59 years old were analyzed, and the characteristics of job stress in 3,290 scientific researchers were compared with those of 1,799 technicians and 1,849 clerks. The researchers perceived higher quantitative and qualitative workload, greater job control (job decision latitude), and greater reward from work, than did the other two job groups. In addition, young male researchers received a large amount of support from their coworkers, while middle-aged male researchers perceived difficulty in personal relationships with their coworkers. From the viewpoints of the demand-control-support model and the effort-reward imbalance model, the researchers, particularly men, were typically occupied in active jobs, and the large amount of effort required for their work seemed to be balanced by greater reward from work. Compared with male researchers, however, female researchers perceived lesser job demand, lesser job control, and lesser reward from work. The working environment of female researchers may be related to the so-called career stress of working women. The mental health status of these scientific researchers should be examined directly in a future study.