Abstract: This apparatus can effect pyrolysis of hydrocarbon containing material at high temperature of 400.degree. to 500.degree. C. and under vacuum in consecutive batches. The apparatus comprises a cylindrical drum rotatable at a variable speed about a horizontal axis and spacedly surrounded by a heat insulating sheath; a gas burner heats the rotating drum along its entire length from the exterior of the same; a chimney communicates with the space between the drum and the sheath, which has ventilation openings closable by trap doors; the drum is supported by bearings so to allow its axial thermal expansion. A manifold system of filters is stationarily mounted within the rotating drum to filter out fine solid residues from the pyrolytic gases and vapors. This manifold is connected to a discharge tube which exits from one end of the drum and is fitted with a sealing joint to seal the drum around the stationary discharge tube.