PURPOSE: To accurately deal with expressions which are different from each other in the word dividing method in accordance with the structure of sentences.

CONSTITUTION: A morpheme analyzing section 2 divides an input sentence inputted from an input section 1 into words and a syntax analyzing section 3 generates a syntax tree and extracts the expression in which a noun predicate is modified in buried state from the generated syntax tree. Then a correcting section 4 collates conditions regarding the description and attribute of a word and the extracted expression, changes the word into the noun predicate including the expression of an attribute representing the phase and time as part of the predicate expression, and corrects the syntax tree based on the change against the noun predicate, for the segment modifying the noun predicate, and another phrase related to the noun predicate and the segment concerning therewith by referring a control rule 8.