The purpose of this study is to investigate factors within visual display terminals (VDT as follows) work related stress reactions in a company. For this purpose, this study developed a scale named the VDT work stressor scale. Based on a result of factor analysis of 15 items, the VDT work stressor scale was found to include three subscales (the qualitative overload concerned with E-mail, the operating trouble and the excessive quantity of E-mail). As a result of multiple regression analysis, it was found that both the excessive quantity of E-mail and the qualitative overload concerned with E-mail significantly associated with mental health. These results suggested the effects of E-mailing within VDT work on mental health.