PURPOSE: To improve the efficiency of KANA (Japanese syllabary)/KANJI (Chiness character) conversion by showing the KANJI (or a sentence including KANJI) which is processed before by supplying the head KANA character to said KANJI containing the independent words and compound words which are once converted for indication of conversion.

CONSTITUTION: A code signal is delivered to a data bus 9 by means of a keyboard device 1. A dictionary control part 7 retrieves a dictionary memory 20 according to a given KANA sentence and read out the corresponding KANJI (or a sentence including KANJI) to deliver it to the bus 9. The work stem part of the output of the bus 9 is supplied to an RAM6 for production of an abbreviated conversion dictionary. A word stem buffer in the RAM6 stores successively the head KANA character, the control information, the word stem character trains. In addition, an abbreviated conversion buffer stores the sentences in the order of their use. When the data is read out, the corresponding word stem is delivered after a fed abbreviated conversion KANA character is supplied as a headword.