The melting treatment is of great promise as treatment technology of volume reduction and stabilization for low-level radioactive miscellaneous solid wastes generated from nuclear facilities. Japan Atomic Energy Research Institute (JAERI) has been developing plasma melting method and carrying out melting tests of simulated miscellaneous solid wastes by this method. This paper describes heating characteristic, distribution behavior of radioactive tracer and volatilization behavior of slag component in the plasma melting. Thermal property of waste material had a great influence on heating efficiency of plasma heating. Uniformity of molten products was confirmed by radioactivity measurements. Residual fraction of Cs-137 in solidified product decreased with increasing of heating times. On the contrary, almost all of Eu-152 remained in solidified product. Volatilization of chemical components from molten slag was observed.