The agitator includes a furnace body that includes a molten metal room, and an agitating unit that agitates molten metal stored in the furnace body. The agitating unit includes a molten-metal driving room-forming part that applies a driving force to the molten metal, and forms a driving room of which both ends are opened; a pair of electrodes that is disposed in the driving room and makes current flow in the driving room under the presence of the molten metal; and a magnetic field unit which is formed of a permanent magnet disposed outside the furnace body, of which one pole of an N pole and an S pole faces the furnace body so that magnetic lines of force generated from the one pole cross the current, and which generates an electromagnetic three for driving the molten metal from one end toward the other end in the driving room.