PURPOSE: To improve the efficiency of KANA (Japanese syllabary)-KANJI (Chinese character) conversion processing, by converting plural KANA character strings at the same time and operating respective devices for KANA to KANJI conversion simultaneously.

CONSTITUTION: An input KANA character string is stored in a storage device 10 for the halfway result of retrieval and test result conversion. A retrieval dictionary determining device 3 fetches the halfway conversion result from the device 10 to determine a dictionary to be retrieved by referring to the contents of a transition table storage device 2, and takes a copy 12 of the halfway conversion result and outputs it to a halfway conversion result storage device 8. A dictionary retrieving device 5 receives a signal from a control signal 1 to retrieve one of dictionary storage devices 4-1W4-n according to the dictionary determined by the device 3; and the device 5 takes a copy 11 of the retrieval result and stores it in a storage device 9 for the halfway result of word conversion together with added grammatical information. A halfway conversion result updating device 7 checks the contents of the device 9. and retrieves a concatenation table storage device 6 by the grammatical information; when the KANA character string can be concatenated to a KANJI character string, it is outputted and when not, it is sent to the device 10. Then, said operations are repeated and the respective devices are put in operation simultaneously.