The filament of MoSi2 for light source was made by the powder extrusion method under the optimized shaping condition. A high temperature of 1600°C in air and high emissibility was obtained. Emitted light power of the new material at 1600°C was higher than that of the conventional light source at 1000°C. Applicability of MoSi2 as a light source was confirmed by testing in the FT/IR system.