To provide a waste material melting treatment system having reduced running cost.

The waste material melting treatment system comprises an incinerator 6 for incinerating waste materials to be treated, a gas quenching tower 13 provided in an exhaust gas system for the incinerator 6 for reducing the temperature of exhaust gas, an exhaust gas side dust collector 15 provided on the downstream side of the gas quenching tower 13, a melting furnace 29 for melting non-combustible materials discharged from the incinerator 6 into slag, a melting furnace side dust collector 39 for trapping soot and dust from the melting furnace 29, a washing means 132 for washing the soot and dust trapped by the melting furnace side dust collector 39, a filtering device 133 for filtering solid components washed by the washing means 132 to obtain filtered residuals, and a pipe 134 in which the filtered residuals obtained by the filtering device 133 is mixed into water jetted from the gas quenching tower 13.