1. A data processing device comprising: a data managing portion which manages hierarchical data having a hierarchical structure with tuples and lists, each of the tuples being a combination of data of different data types, each of the lists being a series of data of a same data type, and at least one attribute among a plurality of attributes that compose a tuple in a level of the hierarchical structure being a list of data in a lower level of the hierarchical structure; a user interface portion which receives hierarchical data, display data obtained by converting the hierarchical data, and an instruction requesting analysis processing on the hierarchical data from a user, and presents the display data and a result of the analysis processing to the user; a display-data generating portion which generates the display data by converting the hierarchical data; an analysis processing portion which receives the instruction from the user interface portion, and implements analysis processing on the hierarchical data in accordance with the received instruction; the user interface portion displaying the display-data; wherein the display-data generating portion samples data of each level of the hierarchical data to extract a part of the corresponding level of the hierarchical data by an amount possible to present on the user interface portion, and converts the extracted data into the display data of a table format having a level-name row for presenting names of respective levels of the hierarchical data, an attribute-name row for presenting names of attributes composing each tuple in respective levels of the hierarchical data, and a plurality of rows for presenting values of the attributes composing the each tuple in respective levels of the hierarchical data.