PURPOSE: To provide a data input device which can perform an easy-to- understand display in a simple operation system.

CONSTITUTION: An input character string analyzing part 220 analyzes the data which are successively read out of a data file 200 of a hierarchical structure storing the addresses, etc., by a retrieving part 210 for each hierarchy and also analyzes such input character strings 240 to 243. Then the data retrieved by the part 210 are shown in the lists 250 to 253 at a list display part 230. A user can selects these data lists by the up-down shifts of a cursor, can decide a common part by a single key in an incremental research where the head matching is retrieved for each input, and also can designate a data list by the head character of a word. Thus the user can easily and fast select the data lists. In addition, the form of the final data can be selected through a candidate form list 253 and furthermore the input and the processing of plural types of data can be simplified since a form can be previously designed. An environment setting part is added to facilitate the display and the selection together with an input support part which starts the retrieving of other dictionaries based on the dictionary retrieving results, a growing key word, etc.