An event management apparatus collects event data which an event extraction unit of each business system extracts on the basis of event extraction definition, and performs queuing to an event queue. An event relation unit makes groups of event data in units of business data, and performs the relative processing of business data to store the event data in an event management DB. When retrieval conditions are inputted from a user terminal, the output unit retrieves the event management DB according to the retrieval conditions, and outputs and displays relation between business data on the user terminal in a tree form.