Chain reaction bankruptcy is regarded as common phenomenon and its effect is to be taken into account when credit risk portfolio is analyzed.But consideration and modeling of its effect leave much room for improvement.That is mainly because method for grasping relations among companies with limited data is underdeveloped.In this article,chance discovery method is applied to estimate industrial relations that are to include companies’ relations that transmit chain reaction of bankruptcy. Time order method and directed KeyGraph are newly introduced to distinguish and express the time order among defaults that is essential information for the analysis of chain reaction bankruptcy.The steps for the data analysis are introduced and result of example analysis with default data in Kyushu, Japan,2005 is presented.The structure estimated by the new method is compared with the structure of actual account receivable holders of bankrupted companies for evaluation. Chain reaction bankruptcy is seen as common phenomenon and its effect is to be taken into account when credit risk portfolio is analyzed. Its consideration and modeling of its effect leave much room for improvement. It is mainly because method for grasping relations among companies with limited data. is underdeveloped.In this article, chance discovery method is applied to estimate industrial relations that are to include companies’ relations that transmit chain reaction of bankruptcy. Time order method and directed KeyGraph are newly introduced to distinguish and express the time order among defaults that is essential information for the analysis of chain reaction bankruptcy. The steps for the data analysis are introduced and result of example analysis with default data in Kyushu, Japan, 2005 is presented. The structure estimated by the new method is compared with the structure of actual account receivable holders of bankrupted companies for evaluation.