The authors present the emission spectra of four types of partial discharges. The purpose was to develop a partial discharge (PD) light detector. PDs in SF/sub 6/ gas-insulated systems (GIS) often indicate a fault in the electrical insulation. Four cases of PD in SF/sub 6/ gas were measured using a needle point discharge, a floating-electrode discharge, and a metallic-particle discharge, which are likely to occur inside a GIS. Spectral measurements have also made of spark discharge caused by glass discharge tubes. The results indicated by the different spectral patterns are discussed.<<ETX>>