A device for biological degradation of organic material and for producing biogas from said degradation, comprising a closed container (4) with a filling opening (12) for the organic material and discharge openings (5, 18) for the degradation products and one or more rotary elements (26) mounted on a shaft (24) and arranged for rotation in the container. Each rotary element (26) comprises at least one plate- shaped element (28; 28a-c) and a moving device (30) for moving the organic material from a first side (30a) of the moving device to a second side (30b) of the moving device. The plate-shaped element comprises a cylinder body (28; 28a-c) connected to the moving device (30), concentrically about the shaft (24).