Recent results of R&D on high current negative ion source at JAERI are ion beam production, the R&D work has been progressed toward longer pulse beam production and the beam optics. A long pulse operation for 24 hours was demonstrated stably with a small cesiated volume source. It was confirmed that the heat load in the source is a modest level allowable for the long pulse operation. The cesium effect lasted for 24 hours, once the cesium was seeded before operation. In beam optics study, we have produced a beam with very small divergent angle of 1.5 mrad. To take this advantage for a design of compact neutral beam system, beamlet focusing technique by aperture displacement was applied in the H−beam extractor.