PURPOSE: To injection mold a metal powder without restriction of particle diameter or shape of the raw powder by providing a screw in a hollow cylinder and the outer periphery thereof to revolve freely in an injection cylinder and by providing a plunger which is fitted to slide freely in the hollow cylinder.

CONSTITUTION: The screw 30 in the injection cylinder 25 revolves by means of the worm 37 and worm wheel 32, and the molding material 27 in the hopper 26 is sent forward to be kneaded and plasticized by heating with the heater 28 and by feed working of the blade 31. When the material fills sufficiently the tip end part of the injection cylinder 25, the plunger 33 is moved forward by a hydraulic device 38 and the material 27 is injected from the nozzle 29 to metal mold at a prescribed pressure.