PROBLEM TO BE SOLVED: To improve separation between the waste straw and the grain and improve the separation performance by enabling two-step separation using a shelf for sieve separation of discharged dust to receive the discharged dust material from the terminal side of a threshing chamber and a sieve line disposed below the shelf.SOLUTION: This grain threshing apparatus includes: a threshing chamber (3) having a cylinder (4) a shelf (14) for rocking separation provided below the threshing chamber (3) and a winnower (26), a first transferring screw (27) and a second transferring screw (28) which are provided in order from the front side below the shelf (14) wherein a shelf (23) for sieve separation of discharged dust adapted to receive the discharged dust falling from the terminal side of the threshing chamber (3) and rock and transfer backward the same to be sieved and separated is provided on the upper part of the shelf (14), and a sieve line (24) adapted to receive the treated material falling from the shelf (23) and sieve and separate the same is provided in the vertical space part between the shelf (23) and the shelf (14).COPYRIGHT: (C)2013,JPO&INPIT【課題】扱室終端側からの排塵処理物を受け入れる排塵篩い選別棚と、その下方に配置する篩い線とによって2段選別を可能とし、藁屑と穀粒の分離を良好にし、選別性能の向上を図る。【解決手段】胴(4)を有した扱室(3)を備え、扱室(3)の下方には揺動選別棚(14)を備え、揺動選別棚(14)の下方には唐箕(26)と1番移送螺旋(27)と2番移送螺旋(28)を前側からこの順に備えた脱穀装置において、揺動選別棚(14)の上部に、扱室(3)の終端側から落下する排塵処理物を受けて後方に向けて揺動移送しながら篩い選別する排塵篩い選別棚(23)を設け、排塵篩い選別棚(23)と揺動選別棚(14)との上下方向での間隔部に、排塵篩い選別棚(23)から落下する処理物を受けて篩い選別する篩い線(24)を設ける。【選択図】 図1