Provided is a superheated steam sterilization device capable of continuously performing sterilization treatment on a large amount of grains and avoiding non uniform exposure to superheated steam even when the amount of grains introduced is large. A superheated steam sterilization device according to one embodiment of the present invention is provided with: a horizontal tubular part having one end at which a supply inlet for supplying an object to be sterilized is formed and the other end at which a discharge outlet for discharging a sterilized object is formed； a rotating shaft part which is rotatably disposed in the horizontal tubular part and includes a helical screw for moving the supplied object to be sterilized and an stirring member having a plurality of stirring blades for stirring the object to be sterilized； a plurality of superheated steam nozzles provided above the horizontal tubular part； a superheated steam box which is provided above the horizontal tubular part is partitioned into a plurality of sections in an axial direction and is for temporarily retaining the superheated steam supplied from the superheated steam nozzle； and a steam discharge outlet for exposing the object to be sterilized which is being moved or stirred in the horizontal tubular part to the superheated steam retained in the superheated steam box.
