1. A method of generating a hierarchical structure including a plurality of elements having parent-child relationships, comprising the steps of: referring to a parent-child relationship table indicating each parent-child relationship between the elements, and generating and outputting a hierarchical structure display table which includes at least information for determining whether each element is a parent element; information for determining whether each parent element is a top parent element; information for determining a child element of each parent element; and information for determining another child element having the same hierarchical level of each child element, so as to analyze the hierarchical structure; and generating and displaying the hierarchical structure of the elements by referring to the hierarchical structure display table.