A dry stirrer configured to stir powder in a dry state, and a wet stirrer provided downward of the dry stirrer in the vertical direction and configured to stir the powder are used. In the wet stirrer, the powder is stirred together with a fluid component, so that granules are formed. The wet stirrer includes a stirring chamber having a cylindrical shape and having a central axis placed in the lateral direction, a cut blade configured to rotate around the central axis of the cylindrical shape in the stirring chamber, and an agitating blade configured to rotate along an inner wall that is a cylindrical side face inside the stirring chamber. When the agitating blade passes above the central axis of the stirring chamber in the vertical direction, the agitating blade is rocked.