Recently concerns on work stress and mental health status of industrial workers were increased. The purpose of this study was to investigate the work stress measured by PSI (psychiatric symptom index) according to socio-demographic variables. The study population was consisted with two types of group; manual and clerical workers. The major findings of this study were as follows; Mean scores of psychiatric symptom in manual workers were higher in female, youth, educated, unmarried and divorced, noisy condition, that in clerical workers was higher in aged. Mean scores of psychiatric symptom were highly affected by degree of work autonomy, self-esteem, and self-efficacy in both groups. The higher the work autonomy, self-esteem, and self-efficacy, the lower the mean scores of work stress it showed. Psychiatric symptom index was explained with the work autonomy, self-esteem, self-efficacy through multiple stepwise regression. The annual admission rates were high in highly ranked groups on each psychiatric symptom dimension.