Abstract: An oscillating grain separator comprised a grain separating plate provided with a rugged surface which oscillates in the angle direction of elevation for shaking up grain and mixed grain is separated at one at front side and/or rear side of the separating plate and flow out sideways from the plate, an oscillating grain separator having photoelectric means consisting of a light source and a light receiving element for detecting the flow conditions of the grain on the grain separating plate and automatically controlling the angle of elevation, mean oscillating angle, frequency or amplitude of the grain separating plate for normal control of the grain flow.