1. A digital information analysis system comprising: a target selection unit that selects target digital information to be investigated which is stored in an information processing apparatus; a combination storage unit that stores each of a plurality of word combinations related to a predetermined specific item; a search unit that searches whether the plurality of word combinations stored in the combination storage unit are included in the target digital information selected by the target selection unit; a relation determination unit that determines the relation of the target digital information to the predetermined specific item on the basis of a morphological analysis result when at least one of the plurality of word combinations stored in the combination storage unit is included in the target digital information; and a determination result setting unit that associates the determination result of the relation determination unit with the target digital information.