PURPOSE: To decrease the KANA(Japanese syllabary)/KANJI(Chinese character) conversion processing time by comparing the number of KANA characters at and after a word retrieving position within an input KANA train with the reading length of the word stored in a word information temporary storage part and displaying the input/ output information after replacement based on the result of comparison.

CONSTITUTION: A keyboard 1 which decides an input key is provided together with a memory part 2 for input KANA train information, a replacement part 3 for said train information, a word dictionary 4 and a word retrieving part 5. Then the word with which the number of KANA characters is detected at and after a word retrieving position is retrieved 5 among the words having the reading length smaller than the number of KANA characters within an input KANA train every time an input KANA is added or deleted. Then the reading lengths of the words with which said number of KANA characters is detected are compared 7 with each other. Based on the result of comparison 7, the information supplied selectively and the output KANJI information are replaced 9. In addition, the input KANA train information and the output KANJI train information are replaced 9 and displayed 10 when the fixture is indicated for the KANA/KANJI conversion result.