PURPOSE: To obtain light oil, fuel gas, etc. through utilizing waste resins, by feeding, in an airtight state, waste plastics to a heating oven to effect gasification through melting in a low-oxygen concentration atmosphere followed by cooling the gas generated.

CONSTITUTION: Waste plastics such as of expanded styrene resin to subjected to crusher 1, being fed to feedstock tank 3 followed by putting into airtight extruder, then continuously feeding to heating oven 7 while preventing air from introducing into the system by press packing said crushed plastics. This feedstock is then heated by burner 13 to effect melting and gasification. The gas thus generated is fed to fractional distillation tower 16, where both heavy oil and impurities, light oil, and gasoline fraction are recovered at tank 16a, tank 16b, and tank 16c, respectively, to feed to fractional distillation cooling tanks 17 and 18; whereas, the exhaust gas from the vent 19 of the tower 16 is scrubbed by alkali in a tower 23 followed by feeding to the oven 7 for use as a fuel gas.