An apparatus for impressing fancy patterns on the outer surface of extrudates of a plastic material, particularly a thermoplastic material. A continuous band or web is inserted between a mould wall and the extrudate outer surface and is fed forward concurrently with the extrudate, negative pressure being employed to imprint on the extrudate the desired patterns which are reproduced on the continuously advancing web or band. Preferably, the band or web is either porous or foraminous.