An information processing apparatus includes: a document analyzing unit that extracts phrases including a pair of entities, to which a relevance label is granted, from document data; and a label granting unit that grants the relevance label. The label granting unit acquires vocabulary syntax patterns included in the phrases including the pair of entities, acquires the appearing number of times the vocabulary syntax pattern appears in the document data from the document data, counts the number of pairs of entities, sets a probability model created from a probability density distribution, a parameter Z indicating validity of the granting of the relevance label, and a parameter a indicating a probability of rightly granting the relevance label, calculates the parameters Z and a for which a likelihood is maximum in the probability model, evaluates the validity of the granting of the relevance label, and grants the relevance label on the evaluation result.