Risk management of medical accident is important to attain better "fabric administration", "Accident correspondence", and "field management". We performed an investigation for actual medical accidents cases. We classified the medical accidents into four factors by using cluster analysis and regression analysis. As a result, rates of malpractices caused by "Carelessness group" had about 49%, Which has much influence on maintaining for our quality of medical cares. We used analytic hierarchy process (AHP) and, from this result, determined strategy of prevention for "the accidents with various medical apparatus". As a result, most effective correspondence was "enlightenment education" and the next was "emergency measure", and then the third was "detailed research". At First, we advance a suggestion "Emergency measure" and "Detailed research" on "Carelessness group". In addition, we suggestion "educations on improvements of Working environment" with applying same schedule for Working Environmental group. Secondly, we suggestion about "administration countermeasure" and "Inexperience research" or "safety control". We got the result that these plans are the most effective counter measures. The AHP analysis countermeasure was thought to be useful tools in all in medical scene.
