The present invention relates to a threshing device for threshing of a material. The threshing device comprises a threshing part with a first rotatable unit (6) which comprises at least a flail (12) and a concave (15) which surrounds the rotatable unit (6). Preferably, the concave (15) is rotatably arranged in an opposite direction in relation to the first rotatable unit (6). The threshing device comprises a cleaning part with a rotatably mounted sieve (16), which surrounds the concave (15). A fan (28) is arranged to provide an air stream towards the sieve (16) for preventing the cleaned parts of the threshed material to pass through the sieve (16). The air stream is also arranged to transport out the cleaned parts which are collected in a space (18) between the sieve (16) and the concave (15).
