A manufacturing method for a cast bar and tube made of a magnesium alloy, includes steps of preparing a manufacturing device; depressurizing a vacuum chamber through a depressurization device; heating a vicinity of an opening of a hollow tube; inserting the opening of the hollow tube into a molten metal; switching a valve member to be open; introducing the molten metal into a cylindrical part, and filling the cylindrical part with the molten metal; cooling the hollow tube; and continuously vibrating the hollow tube until completing solidification of the molten metal in the cylindrical part.