PURPOSE: To qualify an abbreviation word with high accuracy from a processing object character string included in a Japanese language text in which a KANJI (Chinese character) and KANA (Japanese syllabary) are mixed along with word information.

CONSTITUTION: Plural word candidates and pieces of word information of them for the process object character string are acquired, and when the word candidate of one KANJI character which is not satisfying a connection condition between at rear word candidate or which is consisted of a noun exists in the word candidates exists as a retrieval targeted word candidate, a synonym derivable flag, an abbreviation derivable flag, and the meaning attribute of the rear word are acquired, and the word candidate which the retrieval object word candidate is joined with the rear word candidate is acquired, and also, the word information of the retrieval targeted word candidate comprising it is acquired, and a word string candidate is prepared from them, and also, the word information of it is acquired, and the word string candidate in which the number of words in the word string candidate is minimum is qualified as the abbreviation word, and also, the word information of the word is qualified.