A portable scanning device includes a docking seat, a handheld scanner, a positioning unit, a document-feeding unit and a motor. The docking seat has a receiving groove, a feeding groove, a document inlet, and a document outlet. The positioning unit is mounted to the docking seat for retaining the handheld scanner in the receiving groove. The document-feeding unit includes a loading subunit for conveying a document from the feeding groove to the handheld scanner through the document inlet, a discharging subunit for discharging the document via the document outlet, and a regulating subunit for continuous document-feeding action when a plurality of the documents are scanned. The motor is for actuating movement of the document-feeding unit.