An auger snow-removing machine comprising: an auger housing arranged at the front end of the snow removing machine when seen in its forward advancement direction, the auger housing having a width direction extending from a left side to a right side of the snow removing machine; a forward rotation shaft provided with a forward rotation auger and a reverse rotation shaft provided with a reverse rotation auger, the forward rotation shaft and the reverse rotation shaft being disposed on the same axis and aligned in a width direction of the auger housing within the auger housing; and a transmission disposed inside the auger housing such that the forward rotation shaft and the reverse rotation shaft are rotated concurrently in opposite directions by a driving force transmitted from the transmission, wherein the transmission includes: an input shaft to which the driving force is inputted, the input shaft extending in a front-rear direction of the auger housing; a reverse rotation drive shaft connected to the reverse rotation shaft and a forward rotation drive shaft connected to the forward rotation shaft, the reverse rotation drive shaft and the forward rotation drive shaft extending in the width direction of the auger housing; a driving gear provided on the input shaft; a first driven gear provided on the reverse rotation drive shaft and meshing with the driving gear; a counter gear meshing with the first driven gear; an idle gear mechanism for converting rotation of the counter gear to rotation in a reverse direction, the idle gear mechanism having an output gear; a second driven gear provided on the forward rotation drive shaft and meshing with the output shaft of the idle gear mechanism; and a case, characterized in that the case is a split case divided into a front case member and a rear case member at a position behind the reverse rotation drive shaft when seen in the forward advancement direction of the snow removing machine, the rear case member being disposed rearward of the front case member, and in that the front case member has a first gear unit pre-assembled therein, the first gear unit including the input shaft, the reverse rotation drive shaft, the forward rotation drive shaft, the driving gear, the first driven gear, and the second driven gear, and the rear case member has a second gear unit pre-assembled therein, the second gear unit including the counter gear, and the idle gear mechanism, such that the first and second gear units (61, 62) can readily be brought into an assembled state when the front and rear case members (64, 65) are assembled together. an auger housing arranged at the front end of the snow removing machine when seen in its forward advancement direction, the auger housing having a width direction extending from a left side to a right side of the snow removing machine; a forward rotation shaft provided with a forward rotation auger and a reverse rotation shaft provided with a reverse rotation auger, the forward rotation shaft and the reverse rotation shaft being disposed on the same axis and aligned in a width direction of the auger housing within the auger housing; and a transmission disposed inside the auger housing such that the forward rotation shaft and the reverse rotation shaft are rotated concurrently in opposite directions by a driving force transmitted from the transmission, an input shaft to which the driving force is inputted, the input shaft extending in a front-rear direction of the auger housing; a reverse rotation drive shaft connected to the reverse rotation shaft and a forward rotation drive shaft connected to the forward rotation shaft, the reverse rotation drive shaft and the forward rotation drive shaft extending in the width direction of the auger housing; a driving gear provided on the input shaft; a first driven gear provided on the reverse rotation drive shaft and meshing with the driving gear; a counter gear meshing with the first driven gear; an idle gear mechanism for converting rotation of the counter gear to rotation in a reverse direction, the idle gear mechanism having an output gear; a second driven gear provided on the forward rotation drive shaft and meshing with the output shaft of the idle gear mechanism; and a case, characterized in that the case is a split case divided into a front case member and a rear case member at a position behind the reverse rotation drive shaft when seen in the forward advancement direction of the snow removing machine, the rear case member being disposed rearward of the front case member, and in that the front case member has a first gear unit pre-assembled therein, the first gear unit including the input shaft, the reverse rotation drive shaft, the forward rotation drive shaft, the driving gear, the first driven gear, and the second driven gear, and the rear case member has a second gear unit pre-assembled therein, the second gear unit including the counter gear, and the idle gear mechanism, such that the first and second gear units (61, 62) can readily be brought into an assembled state when the front and rear case members (64, 65) are assembled together.