The Japanese Society for Occupational Mental Health has conducted research on assessment of the psychological load（i.e., stress）among workers. Investigations were conducted three times,and those were contract research projects assigned by the Ministry of Health, Labour and Welfare. In this project, the author was the primary researcher. In the latest research, a survey utilizing the Live Event Method was performed extensively nationwide; the survey covered 10,494 subjects（including 1,977 females）from all types of industry and occupation. The objective of this research was to reevaluate the Psychological Load Assessment Sheet used as an evaluation basis for the“Certification of workers’compensation related to mental disorders from psychological load.”Two previous research investigations, conducted in 2002 and 2006, had suggested the need for such reevaluation.
 The outcomes revealed that,the longer the monthly overtime working hours,the higher the stress scores（in the range of 0 to 10）, and the lower the appearance rate of stress. Subjects who performed 140 hours or more of overtime work per month,which fell under the category of“Extremely Excessive Overtime Work,”showed 6.3 points,which was markedly high, and ranked fourth in the survey with 63 assessment items. The category, “Extremely Excessive Overtime Work,”includes two working hour ranges, 120 hours or more and 160 hours or more; those working hour ranges were defined in the revision based on the latest research. Monthly overtime work of 120 hours or more, but less than 140 hours,was ranked ninth and scored 6.3 points.
 Monthly overtime work of 80 hours or more, but less than 100 hours, scored 5.3 points with a frequency of 14.2%.Based on the above results,new assessment items were added to the Psychological Load Assessment Sheet.
 This paper addresses and studies the issues explained above.