We have been researching to develop a supporting system for enabling safe operation based on the cognitive model that is about the complex casual relationship of the state of facilities and steel for the continuous casting process. This research aimed to propose the text mining methods for updating and maintaining the cognitive model for the continuous casting process using accident trouble reports. Three kinds of description model are proposed as an inputting model from trouble reports. State Diagram and Causal Relationship Diagram are used to describe them from the detail and holistic viewpoint. This research arranged a flow of text mining and proposed new method that can suggest the necessary information for updating the model of continuous casting process by making and defining those models stage by stage.