To improve the treatment capacity of a plastic treatment apparatus by increasing the vaporization area of a liquified molten plastic; and to enable the treatment apparatus to be conveyed by constructing the whole of the apparatus compactly and accommodating its main part in a casing.

The apparatus has a drying section 1 having a hopper 7 and an almost horizontally arranged vaporization section 6 installed below the drying section 1. In each of the sections 1 and 6, a lead screw 11 is installed. A crushed plastic and a residue are sent under heating to the vaporization section 6 to be vaporized, and this vaporized gas is cooled to give an oil or is directly sent to a boiler or the like to be used as a fuel.