There are many marine accidents by human factors. Experiments with bridge simulator are effective for analysis of human factors. Analytical approaches with bridge simulator have already been conducted. But analytical method with bridge simulator hasn't been established yet. The purpose of marine accident analysis is identification the cause of marine accidents and consideration of accident countermeasures. In previous report, we detected an error that could have been occurred in a collision accident through the expression with simple task model like event tree. But in order to identify the cause of the accident, it is necessary to confirm the process of detected error. In this study, we propose a method to identify the process of judgment error on collision risk by modeling judgment patterns. In the result of modeling judgment patterns, it was made clear that the cause of the collision accident was the judgment errors of the targets' navigational position.
