1. A document verification method for an apparatus for verifying a binder document which includes multiple documents, the method comprising: a determination step of determining, for each document included in the binder document, whether the document is a verification target document or not; a verification step of verifying a document which has been determined as the verification target document in the determination step; and an output step of outputting the result of verification of the binder document, on the basis of the result of the verification of the verification target document.