To provide an agitation vessel capable of shortening an air path and being rolled and rotated to sterilize granules by irradiating weak electron beams on the granule surface.

One mechanism of agitation is to uniformly irradiate the electron beams on the whole surface of a substance to be treated by vertically vibrating the agitation vessel having a planar bottom board around a central shaft installed in the center of the bottom and agitating the substance to be treated which is put into the agitation vessel. The other mechanism is to irradiate the electron beams to the whole surface of the substance to be treated by laterally and reciprocally moving the agitation vessel having a bottom plate with a circularly concave surface around the central line parallel to the longitudinal direction of an irradiation window and laterally rolling and shaking the substance to be treated.