<p>PURPOSE: A method and an apparatus for processing plastic wastes are provided to control gas composition by manufacturing desired synthetic gas within a plasma furnace and to obtain high recycling rate and energy recovery rate of the plastic wastes by reducing unreacted substance and side reaction. CONSTITUTION: A method for processing plastic wastes comprises the following steps: a pyrolysis step(S10) heat-decomposing the plastic wastes; a pyrolysis residual isolation step(S21) separating the pyrolysis residual from gaseous products; plasma reaction step(S20) creating desired gas by reacting the gas created in the pyrolysis step with oxygen or steam using plasma; a cleaning step(S30) eliminating unnecessary component by washing the created gas; and a gas recovery step(S40) collecting the gas passing through the cleaning step.</p>
