The　electrical　properties　of　a　nonvolatile　organic　bistable　device　(OBD)　utilizing　Au　quantum　dots　(QDs)　sandwiched　between　two　thin　insulating　polyimide　layers　were　investigated.　Current-voltage　(I-V)　measurements　on　the　device　at　room　temperature　showed　a　current　bistability　due　to　the　existence　of　the　Au　QDs.　The　maximum　ON/OFF　ratio　of　the　current　bistability　in　the　OBD　was　1　×　108,　the　largest　value　ever　reported　for　a　stable　OBD.　The　device　has　excellent　endurance　and　retention　ability　in　ambient　conditions.　The　electrical　properties　and　operating　mechanisms　for　the　device　are　analyzed　on　the　basis　of　the　I-V　results.　©　2011　The　Japan　Society　of　Applied　Physics.