This paper describes the measurement of temperature distribution and radiant flux distribution in the EDM arc plasma using the spectroscopic analysis. These distributions were obtained by the use of a lens which magnifies the image of the plasma and a mask which can limit the plasma region to be observed. The temperature distribution was computed from the radiant flux by the line pair method. This paper investigates first the influence of working conditions on the temperature distribution. Secondly, observing the radiant flux distribution in the plasma, the rate of evaporation of the electrode materials is estimated in order to understand the material removal mechanism. Thirdly, decrease in the plasma temperature during the discharge interval is measured in order to estimate the time required for the plasma to be deionized.