PURPOSE:To make it possible to perform the stirring of a kneaded powder material and strong extrusion thereof, by rotating a screw contacting with the extrusion port of an inverted conical case main body at the lower end thereof by a planet gear revolvable and rotatable around a gear fixed to the periphery of the center line of said case main body. CONSTITUTION:In a case main body 1, the inner surface thereof is formed into an inverted conical shape to constitute an equilateral triangle vertical plane F on each radius line at right angles relative to the center line SL thereof and an extrusion port 2 is provided to the lower end center thereof while a case lid 5 is attached to the upper opening of the main body 1 to cover the same. A freely rotatable drive shaft 10 is inserted through the center of said lid 5 and a fixed gear 20 concentric to the shaft 10 is attached to the rear surface of the cover 5 around said shaft 10. In addition, a planet gear 22 around the center line S of the equilateral triangle vertical plane F is brought into engagement with the gear 20 and the center shaft 23 of the gear 22 is supported by the bracket 24 fixed to the shaft 10. A disc 28 rotatable within the equilateral triangle vertical plane F is fixed to the center shaft 23 and a stirring extrusion screw 29 is provided to the eccentric position of the disc 28 so as to be extended to the vicinity of the extrusion port 2.