This study predicts damaging risk factors in apartment fire situation by using CFAST. The software was developed by Building and Fire Research Lab, that is government affiliated organization of the National Institute of Standards Technology. This analysis scenarios werec well verified by experimental results. Situation of the living room and the second room as well as the bedroom tends to be qualitatively the same with the experimental data. In case of apartment fire, it is predicted that they have been got into trouble with dizziness, badly vomiting and paralysis symptoms due to short oxygen and excessive carbon dioxide when persons were left out in the living room or second room.