A　new　rare-earth　borate　Er6B4O15　was　synthesized　by　a　solid-state　reaction　technique.　The　crystal　was　obtained　by　a　flux　method.　Single-crystal　X-ray　diffraction　analysis　revealed　that　the　crystal　structure　is　composed　of　ErO6　polyhedra　sharing　edges　and　BO3　groups.　The　absorption,　near-infrared　fluorescence　spectra　and　the　fluorescence　decay　curve　of　Er:　4I13/2　energy　level　in　the　Er6B4O15　crystal　were　measured　at　room　temperature.　The　absorption　peak　was　located　at　977　nm　with　absorption　cross　section　of　1.16　×　10−21　cm2　and　a　full　width　at　half-maximum　(FWHM)　of　16　nm,　which　is　very　suitable　for　commercial　980　nm　laser　diode　pumping.　A　maximum　emission　peak　at　1560　mm　with　a　broad　FWHM　of　64　nm　was　observed　in　this　crystal　because　of　the　Er3+　transition　4I13/2→4I15/2,　while　the　emission　cross　section　was　calculated　to　be　8.53　×　10−20　cm2.　These　results　imply　that　the　Er6B4O15　crystal　is　a　promising　candidate　material　for　the　achievement　of　an　eye-safe　near-infrared　wavelength　laser.　©　International　Union　of　Crystallography,　2018