To provide an extruding device which can remove a large sized object without stopping operation.

The device for extruding a viscoelastic material comprises two (2, 3) or several kneading and conveying screws positioned coaxially and concentrically in a body (1). Orifices (22) allowing the space swept by the flights (21) of the larger-diameter screw (2) to communicate with the space swept by the flights (31) of the immediately smaller-diameter screw (3) are provided. A fixed cylindrical tube (4) comprising apertures (41) passing through the wall of the cylindrical tube is inserted between the above both mutual spaces. The space swept by the flights of the larger-diameter screw is closed off by a wall (43). The wall (43) has an orifice (42) communicating with an outfall (52, 62) closed off by a removable blanking means (61).