To provide a metadata generating device capable of automatically generating metadata based on existing data.

A document is inputted (S1), and a subject concept is extracted from the document (S3), and metadata constraint definition including the subject concept is retrieved from a metadata constraint definition storing part 14 (S5), and an object concept is extracted from the retrieved metadata constraint definition (S11), and metadata including a word concept equal to the extracted object concept are retrieved from the metadata storing part 13 (S13), and a word is extracted from the metadata (S17), the word is retrieved from the document (S21), and when the word is present in the document, the subject is extracted from the document (S25), and a predicate is extracted from the retrieved metadata constraint definition (S27), and the metadata constituted of the subject extracted from the document, the predicate extracted from the retrieved metadata constraint definition and the object equal to the word extracted from the metadata are generated (S28).