1. A word retrieval device, comprising: an analyzer configured to carry out morphological analysis of text; an extractor configured to extract at least one word representing a feature of the text from words of a morphological analysis result by the analyzer, using word information quantity on the words; and a retrieval device configured to retrieve text related to the at least one word from a web page using the at least one word as a retrieval query, wherein the word information quantity is represented by I x , where T x represents a power of an appearance frequency of each word and I x is defined as follows: I x = T x ∑ x = t ⁢ ⁢ T x × 100.