In analyzing an elaborate computer system which requires large-scale or numerous event propagation models, a law-of-causality matrix gains size, so that significant amount of storage resources has been used in a management computer. To solve such a problem, the management computer to manage the computer system stores topologies, event propagation models, and causality information including one or more causal relations in the storage resources, determines, when the management computer analyzes or detects an event, whether a causal relation has already been created for the event to be analyzed, and creates the causal relation based on a topology and event propagation models, if not yet.