1. An information analysis device that uses a plurality of linguistic expressions as an analysis target, comprising: a link information generating unit and a correlation value calculation unit, wherein the link information generating unit extracts time information included in each of a plurality of electronic documents including at least any one of the plurality of linguistic expressions and a relationship between the electronic documents in the plurality of electronic documents from the plurality of electronic documents, detects a link between one linguistic expression and another linguistic expression in the plurality of linguistic expressions and an appearance time of the link based on the extracted time information and the relationship between the electronic documents, and generates link information specifying the extracted link and the appearance time of the link, and the correlation value calculation unit specifies the number of appearances of links between the one linguistic expression and the other linguistic expression and an appearance time of each link based on the link information, and calculates a correlation value between the one linguistic expression and the other linguistic expression according to a degree that the link continuously appears by using the specified number of appearances of the link and the appearance time of each link.