PURPOSE: To lighten the input load on an operator, to prevent input errors and to give the alarm of a non-exsiting KANJI (Chinese character) by displaying only the appropriate KANJI from converted KANJI candidates by referring to a related dictionary and giving the alarm when no appropriate KANJI is present at the time of inputting a KANA (Japanese syllabary) in a related item to convert it to KANJI.

CONSTITUTION: This system is provided with the related dictionary 9 for registering data to be inputted to a related item beforehand and a conversion data deciding part 4 for deciding the registered KANJI within the KANJI candidates for which KANA (Japanese syllabary) inputted to the item is converted to the KANJI by referring to the related dictionary 9 and is constituted to display the KANJI decided by the conversion data deciding part 4 in the item. Then, the conversion data deciding part 4 decides the registered KANJI by referring to the related dictionary 9 within the KANJI candidates for which the KANA inputted to the item is converted to the KANJI, the decided KANJI is displayed in the item and the alarm indicating nonpresence in the related item when the dicided KANJI is not present is displayed.