NOVELTY - The method involves shielding upper-end opening of bottomless cooling crucible (10) by shutter (30) when air-evacuating the inside of chamber (1). Cutoff valve (5) of inert gas inlet tube (4) is set closed. Vacuum pump (24) of piping (23) for air-evacuation is operated in state which set open each cutoff valve (21,25) of vent pipe (20) and piping, without operating exhaust pump (8) of exhaust pipe (7). Cutoff valve of inert gas inlet tube is opened when filling inside of chamber with inert gas. Cutoff valve of vent pipe is opened when cooling the ingot (19) within chamber.    USE - Electromagnetic casting method of silicon ingot for substrate of solar cell.    ADVANTAGE - Since the upper-end opening of cooling crucible is shielded by the shutter in the case of the gas replacement in chamber before casting, the foreign material falling in cooling crucible can be prevented. Since the flow of atmospheric gas in chamber becomes facing down by interrupting the circulation of atmospheric gas to vent pipe in the case of continuous casting, the problem that foreign material taken-in in atmospheric gas in the downward direction of the cooling crucible is carried right above cooling crucible, and fallen in molten silicon can be prevented. Hence the molten silicon contaminating with foreign material during operation can be suppressed. The quality silicon ingot can be manufactured.    DETAILED DESCRIPTION - The shutter is evacuated and upper-end opening of crucible is opened when continuously casting dissolving the silicon raw material (14). The exhaust pump is operated in state which switched cutoff valves of vent pipe and piping to close, without operating vacuum pump. The silicon raw material is injected into crucible with electro-conductivity arranged in chamber and dissolved by electromagnetic induction heating from induction coil (11) which surrounded crucible. The shutter is used to open and close the opening to the just overhead of the upper-end opening of the crucible. The inert gas inlet tube is connected with the upper wall of the chamber. The exhaust pipe is connected with the lower side wall of the chamber, and connected with exhaust pump. The piping is branched from vent pipe and connected with vacuum pump. The cutoff valve is arranged to open and close each path by inert gas inlet tube, vent pipe, and piping. A pressure control valve (9) is arranged by exhaust pipe. The flow volume of the inert gas introduce in the chamber through the inert gas inlet tube is 50 liter/minute or more. An air blower (22) is used to send-out the gas within the path downward and arranged by the vent pipe. The air blower is not operated when continuously casting dissolving the time of filling the inside of chamber with inert gas, and raw material when air-evacuating inside of chamber. The air blower is operated when cooling the ingot within chamber.    DESCRIPTION OF DRAWING(S) - The drawing shows a cross-sectional view illustrating the structure of the electromagnetic casting apparatus of silicon ingot. (Drawing includes non-English language text)    Chamber (1)    Inert gas inlet tube (4)    Cutoff valves (5,21,25)    Exhaust pipe (7)    Exhaust pump (8)    Pressure control valve (9)    Cooling crucible (10)    Induction coil (11)    Silicon raw material (14)    Ingot (19)    Vent pipe (20)    Air blower (22)    Piping for air-evacuation (23)    Vacuum pump (24)    Shutter (30)