1. An approval device comprising: a storage circuit that stores a face image database, the face image database registering face image data of at least one user to be an approver for approving a document; a document acquiring circuit that acquires the document; an imaging circuit that images a face of the approver for approving the document; a face recognition circuit that analyzes an imaged face image of the approver and searches the face image database stored in the storage circuit using the analysis result; an approval circuit that approves the document based on the search result; and an editing circuit that attaches one of an electronic stamp and an electronic signature to the approved document.