PROBLEM TO BE SOLVED: To provide a thresher which can prevent the deterioration of the sorting performance of grains by a sorting chamber caused by chips or the like generated at threshing processing, in the thresher having a threshing cylinder which is rotationally driven around a rotating shaft in a vertical direction, and a plurality of threshing teeth formed in a comb shape by being aligned in parallel along an axial direction of the threshing cylinder.SOLUTION: A thresher comprises: a threshing cylinder 6 which is rotationally driven around a rotating shaft 31 in a vertical direction in a threshing chamber 2 and a transfer body 4 which holds and transfers plant foot sides of grain culms in a state that ear tips of the grain culms are oriented toward the threshing cylinder 6 side. A plurality of threshing teeth 32A formed into a comb shape by being aligned in parallel along an axial direction of the threshing cylinder 6 are arranged at the external peripheral face side of the threshing cylinder 6, and the grain culms transferred by the transfer body 4 are threshed and processed by the rotating threshing cylinder 6, a sorting chamber 3 for sorting the grain culms from processed objects which are threshed and processed is arranged immediately below the threshing cylinder 6, and a fall prevention member 57 is arranged which prevents the fall-down of at least a part of objects not to be sorted other than the gains which are released from the grain culms during the threshing processing is arranged.
