¹⁰Be was produced by neutron irradiation of boron nitride and beryllium metal. As for beryllium metal sample, ¹⁰Be was enriched by an isotope separator at the Institute for Nuclear Study. As for boron nitride sample, an isotopic abundance of ¹⁰Be was measured by the surface ionization method. The mass spectrum was obtained for 3.0×10^-9g of ¹⁰Be in the presence of the same quantity of ⁹Be, mounted on a rhenium single filament with silica-gel. The amount of beryllium was determined by isotope dilution analysis. The discrimination factor of beryllium was estimated to be 1.05 per one mass unit