The present invention provides a method of reutilization and method of shaping of waste plastic which reduces the amount of volatile ingredients and oil cake* to extents preferable as materials for coke ovens, enables the formation of plastic granular materials able to maintain suitable shapes even after charging into a coke oven, and does not require expensive facilities for treating any produced hydrogen chloride gas, that is, a method of reutilization of waste plastic characterized by melting waste plastic at over 160° C. to 250° C. in temperature in part or whole, compression shaping it to thereby obtain a plastic granular material having an apparent density of 0.7 to 1.2 kg/liter, and mixing this plastic granular material with coal for dry distillation in a coke oven. By bringing the gas produced at the time of compression shaping the waste plastic into contact with water or an ammonia solution and combining the water or ammonia solution with an ammonia solution of an ammonia solution treatment facility attached to the coke furnace, it is possible to remove the hydrogen chloride contained in the produced gas.