A data retrieving apparatus having: an input apparatus for inputting the hierarchical structure data showing the hierarchical structure and operation instruction data; a data storing apparatus for storing the inputted hierarchical structure data; a retrieving apparatus for retrieving data which satisfies conditions from the hierarchical structure data stored in the data storing apparatus on the basis of the operation instruction data which is inputted by the input apparatus; and an output apparatus for outputting the retrieved data. Each data which is stored in the data storing apparatus has items regarding an efficient date and items regarding a data change date. The retrieving apparatus has an apparatus for retrieving the data on the basis of the efficient date and the data change date.