A slip-resistant and portable scanner for scanning a document placed on a document platen includes a housing, a scan window, and a scanning module and a slip-resistant structure. The scan window is mounted on the housing to closely face the document. The scanning module is disposed in the housing to scan the document through the scan window. The slip-resistant structure is disposed on and attached to a surface of the scan window facing the document and in contact with the document or the document platen. Thus, it is possible to prevent the scan window from slipping relatively to the document and enhance the scan quality and convenience.