A waste plastic treating method and an apparatus are provided to prevent various harmful matters from being generated, by producing plastic resin and H2(Hydrogen-2) gas as by-products. A waste plastic treating method comprises the steps of: crushing waste plastic; pouring the crushed waste plastic into a waste plastic treating device; applying compression friction heat while heating the input waste plastic by a ceramic heater, and melting the waste plastic by a hydrogen molecule separation method adopting induction heat; hydrogenating the melted material by adding an alumina carrier; melting and crystallizing the hydrogenated material in a vacuum distillation device; and synthesizing C2H4(Ethylene) and C6H6(Benzene) by cooling down obtained crystals and generating H2 gas as by-products. The hydrogen molecule separation method is executed by applying high-voltage electricity of 3kW and super-high frequency of 2,450MHz in an induction heat device(12-1).