Provided is an expression extraction device for extracting evaluation
expressions from text having descriptions on evaluations of a specific
evaluation target, which includes a registered expression storage unit
for registering an evaluation expression including a predetermined
polarity as a registered expression, an expression extraction unit for
extracting multiple evaluation expressions and a conjunction expression
from the text, a registered expression detection unit for detecting the
evaluation expression including the registered expression registered with
the registered expression storage unit out of the multiple evaluation
expressions, and a polarity judgment unit for judging that the evaluation
expression, which is in conjunction with the evaluation expression
including the registered expression by means of the conjunction
expression in a form of ordinary conjunction, and the series of
evaluation expressions, which are not in conjunction with the evaluation
expression by means of the conjunction expression in any form of the
ordinary conjunction and adversative/concessive conjunction and are not
in conjunction with each other by means of the conjunction expression in
any form of the ordinary conjunction and the adversative/concessive
conjunction, are of the same polarity as the registered expression.