Though much attention has been paid to mental health particularly depression of working population in Japan partly because the suicide rate maintains high, few research projects were conducted on the knowledge and desirable coping strategies for the prevention of depression. The purpose of this preliminary study was to examine the mental heath literacy of depression among industrial workers focusing on the knowledge on depressive symptoms and possible coping strategies. A total of 278 workers of the Tokyo headquarter of a relatively large company participated in a questionnaire survey which contained a vignette of a person with features of major depression. It was found that only 15.5% of the participants correctly identified the person as suffering from depression. As for the coping strategies, men were more likely to cope with mental health problems by themselves where as women tended to “have a rest” or “seek for help from friends and a counsellor”. In addition, It was indicated that older workers (50 and over) and those who could identify the person with depression were more willing to seek for professional help such as a counsellor. The results suggest that mental health literacy of depression is quite poor and the possibility of choosing undesirable coping strategies is high among Japanese workers. Further study is definitely needed to collect more general data for the development of effective health educational programs to prevent workers becoming mentally ill.