PURPOSE: To rapidly retrieve and display a desired item even when the number of retrieving character signals is increased by using a constitution in which screen data pointed by the pointer of the retrieving character string retrieved from an index character string table is displayed.

CONSTITUTION: A hierarchical structure, what is called in which an index table 1 for storing the leading one character of the retrieving character string 1 and the index character string table 3 for storing a group having the leading one character is provided. A relevant character in an index table 2 for storing the leading one character of the retrieving character string 1 is detected, thereby, the relevant group in the pointed index character string table 3 is retrieved to detect a desired retrieving character string. Further, the screen data corresponding to this retrieving character string is read and displayed. Thereby, the retrieving character string even at the end of the index character string table 3, for instance can be rapidly retrieved to display the desired screen data.