According to one embodiment, a document analysis apparatus is an apparatus comprising first document storage circuit for storing first documents that include words, belong to respective categories constituting a hierarchical structure, and only comprise opinion documents for a desirable object, and a second document storage circuit for storing second documents that include words, belong or do not belong to the categories constituting the hierarchical structure and comprise opinion documents for the desirable object and documents other than the opinion documents, and the apparatus is configured to classify, into one of the categories constituting the hierarchical structure, the second documents that do not belong to the respective categories among the second documents stored in the second document storage circuit.