The present inventions are characterized by providing a processing device, processing method and saccharifying method for extrusion cooked beer adjunct so that the saccharification and filtration of mash for the extrusion cooked beer adjunct may be carried out smoothly in the actual production for brewing beer. As compared with the double-mash saccharifying method (including the saccharifying method with additional enzymes) applied currently now, it may omit the mash cooking procedure and the cooking kettle and put the malt grist and the grist of extrusion cooked beer adjunct together into water in the brew kettle or the grist of extrusion cooked beer adjunct, malt grist and water are together put into the brew kettle to carry out the saccharifying. The single-mash saccharifying method of this invention may reduce the energy consumption, decrease the cost of beer production, increase the recoverable ratio of wort extract and raise the beer output.