PURPOSE: To provide a device, which can be produced at low cost by a maker and which can easily be cleaned by a user at the finish of operation and at the changing-over of material, for continuously molding sheet-like preforming material having the predetermined width and thickness out of a lump of high viscous material kneaded with a batch-type kneader.

CONSTITUTION: The device concerned consists of a conical twin-screw extruder 1, the tips of two rotors 12 of which incline downwards, a large diameter bottom side pressure roll 2b, which is arranged near the lower end of the tip opening 11a of the casting 11 of the screw extruder 1, and a small diameter upper side pressure roll 2a, which molds sheet-like material together under the condition that the predetermined nip is held between the bottom side pressure roll 2b and the upper side pressure roll 2a and is arranged separated from the upper end of the tip opening 11a so as to form material bank W on the upper outer periphery of the bottom side pressure roll 2b.