This study examined maritime disasters, specifically the capsizing of fishing boats, based on marine accident investigation reports issued by the Japan Transport Safety Board（2009-2013). In addition, the Domino theory, advocated by Mr. F. E. Bird Jr., was applied to analyze the cause of the accidents. The results are as follows:（1）of the total number of maritime disasters, capsizing accounts for 75% of fishing boat disasters of boats less than 5 gross tonnage；（2）the fishing types predominantly involved in capsizing disasters are gill net, cage, pole and line, beam trawl fishing, and scallop culture；（3）capsizing disasters occur mostly in calm conditions and are caused by human error；（4）the amount of human damage from these accidents is enormous in that the probability of dying or becoming missing was 35% per accident; and（5）when the causes of the accidents were analyzed by the Domino theory, improvements to the "basic concepts" stage, fishing operational judgment, ship handling, or operation method could be effective in accident prevention. In the future, it will be necessary to collect information in detail from marine accident investigation reports, the Japan Fisheries Cooperatives, and fellow working ships for effective prevention measures according to individual situation, fishing types and boat class.