A screening device for separating dry granular material into a fine fraction and a coarse fraction is provided. The screening device includes a drum screen defined by an open rotatable frame, which frame defines a circumferential wall, and a sheet-like screen arranged over the circumferential wall of the frame. The screening device also includes a driving device by means of which the drum screen is rotatably driven, a feed opening at a short end of the drum screen and a discharge opening at the opposite short end of the drum screen. The screening device further includes a vibration device which rotates along with the drum screen, which vibration device includes one or more vibrating elements mounted to the drum screen, which set the drum screen vibrating in use. A method for separating dry granular material into a fine fraction and a coarse fraction is also provided.