PURPOSE: To drastically enhance the efficiency of KANA (Japanese syllabary)/KANJI (Chinese character) conversion and its hit ratio by providing the KANA/KANJI conversion with a conversion dictionary optimized for each field, whereby in order to convert data input by the keyboard into a KANJI, the conversion dictionary selectively specified by the operator is used for the execution of the conversion.

CONSTITUTION: A conversion means 3 uses the identification number of a registered dictionary specified by a business program 2 to determine a dictionary for conversion, dictionary 5, as an example. Further, the dictionary 5 is used to carry out the conversion processing, and a display means 4 is informed of resultant 'KANJI data'. The display means 4 displays the KANJI data on the screen and waits for information for determination to be supplied from an input means 1. When a KANJI is determined, the application program 2 requires the input means to input next Japanese language data. The converter provides a conversion means 3 with 'KANA' data input from the input means 1 and the identification number of a dictionary in use. Then, the identification number of the dictionary can be arbitrarily chosen from 5-7. The conversion means 3 determines from the numbers of the dictionaries registered of which the application program 2 informed a dictionary to be used for conversion and executes the conversion processing as required.