It is an very important problem what kind of fact the party who charges the insurance should prove by an insurance action. This study treats which party concerned should prove fact of external focusing on a personal accident insurance case. It is an important point specific contents that make up the fact of external, that is what is also included the fact that there is no disease in the body of the insured person. This study is intended to be examined while comparing Korea and Japan precedents and theories for such problems. Burden of proof of legally sufficient cause relationship that the facts and the results injury has occurred that is a function of the body from the outside is in the insurance claimants. Therefore, when two such fact has been demonstrated, it should be interpreted as also estimated that there is no disease insured. As a result, the fact that there is no disease in conjunction with external should be proven to the insurer. Such conclusion is based on the following basis. First, it’s that an insurance consumer should be protected. It’s meant that it’s very difficult to prove no disease insured in particular. The next is that no disease insured is a disclaimer in policy condition.