Fukushima Daiichi Nuclear Power Plants suffered serious damage by the Great East Japan Earthquake and Tsunami. The employees of the plant worked very hard to stabilize the nuclear reactor and to prevent any secondary accidents. They were in one of the most severe situations in this disaster, but they were the people who hesitated most to request help for themselves. We started visiting the Fukushima Daini Plant office that was used as the frontline base for Daiichi Plant workers since July, 2011. These visits were held once or twice a month and we offered mental health support to the employees. We have completed interview with the total number of 339 plant workers by April, 2012. We offered several ways of mental support including clinical treatment, continuous counseling, or one time advice, depending on mental condition of each interviewee. Complexity of huge disaster and individuality of suffering from it were discussed in this article. Like local residents, many plant workers also experienced death/missing of family, loss of housing, refuge life, and dispersion of family. Furthermore, they have been suffering from various kinds of criticism and slander against Tokyo Electric Power Company. Many workers, even though they were not in management positions, seemed to have guilty conscience and sense of responsibility that forced them to stay in the risky working site. We could find some struggling coexistence of sense of guilt (as a causer of disaster) and sense of victim in their mind. It was suggested that continuous effort to listen and pay attention to their talk is important in order to support their mission to stabilize the power plant and to prevent them from over-stress and burnout.