An optically pumped polarized H−source (OPPIS), which is based on the charge exchange between H+ions and electron‐spin polarized alkali atoms has been developed at KEK. Just by applying this scheme to a deuteron beam, it is difficult to obtain a highly vector polarized deuteron beam. To obtain highly vector polarized D−ions, we have developed a ‘‘dual optical pumping type’’ of polarized D−source. With this scheme, a 100% vector nuclear‐spin polarization for D−ions is possible in principle. In a preliminary experiment, a 60% vector nuclear‐spin polarized D−ion was obtained.