A pouring method and a device in a vacuum sealed process to produce a thin-wall cast by using a mold framing for the a vacuum sealed process, and a as-cast product using the pouring method are provided. The pouring method comprises the steps of: sealingly covering the surface of a pattern plate by a shielding member; placing a mold framing on the shielding member and then putting a fill that does not include any binder in the mold framing; sealingly covering an upper surface of the fill and then evacuating an inside of the mold framing to suck the shielding member to the fill to shape the shielding member; removing the pattern plate from the shielding member, thereby forming a mold half that has a molding surface; forming another mold half in a similar way and mating the mold halves to define a molding cavity; pouring molten metal in the molding cavity; and releasing the negative pressure in the mold framing to take out a as-cast product, and further comprises the step of decompressing the molding cavity before pouring molten metal in the mated mold.