1. A document classification and inspection system that obtains digital information recorded in a plurality of computers or servers, analyzes document information configured by a plurality of documents, included in the obtained digital information, and assigns a classification code indicating the degree of relevance with an inspection case to a document to make easy use of the inspection case to inspect the degree of relevance between the inspection case and the document, comprising: a score calculating unit that extracts a document from the document information and calculates, with respect to the extracted document, a score indicating the strength of connection of the document and the classification code in a time series manner; a score change detecting unit that detects a time-series score change from the calculated score; and a score change determining unit that inspects and determines the degree of relevance between the inspection case and the extracted document from the detected time-series score change.