Normal spectral emissivity of Si melt in visible and infrared regions was determined by the direct measurement of thermal radiations from the melt and a blackbody cavity which was located close to the melt. The spectral emissivity slightly decreases with wavelength. The emissivity slightly changes with temperature. The spectral emissivity values in visible and in infrared region are 0.27 and 0.21, respectively. The wavelength dependence of the emissivity can be interpreted by a dielectric response of free electrons in the melt. ©1997 American Institute of Physics.