To mass-product powder metallurgical products without burr and unnecessary deformation, and flaw at a low cost by inserting a press-formed compact in a rotary container inclined obliquely upward before sintering, and spouting plastic projection material from an opening of the rotary container while being rolled to remove burr.

When a motor 8 is started, a rotary container 11 is rotated centered on an axis A-A of rotation in the inclined state, and in the interior of the container, compacts 3 before sintering are raised along the inner wall of the rotary container 11 to a certain degree in the rotating direction and slid to be rolled in the stirring state. In such a condition, a plastic projection material comprising a melanin resin and a urea resin is overall sprayed from a nozzle 23 to the rolling compacts 3, whereby burr formed on the compacts 3 can be all removed by rolling in the rotary container 11 and the spouting of plastic projection material.