This article presents the results of theoretical studies of the interaction of the separation apparatus of the roller type with the object of cleaning. The subject of these studies is highly specialized and relates to the field of agricultural engineering. Tobacco plants were chosen as the object of treatment. The aim of the research was the theoretical substantiation of the interaction of tobacco stems with spiral rollers of the leafseparating apparatus in the process of harvesting. The article analyzes the technologies of tobacco leaves harvesting, tobacco harvesting machines designs, as well as the main reasons for the unsatisfactory work of existing leaf-separating machines of domestic and foreign production in tobacco harvesting of domestic selection varieties. The design and technological scheme of the leaf-separating apparatus for harvesting tobacco leaves is presented. The technological process of work of the separating device of the roller type of the developed design is given. A theoretical analysis of the interaction of the tobacco stem with the spiral rolls of the leaf-separating apparatus is carried out. As a result of the research, dependences were obtained that allow to determine the design and technological parameters of the separating apparatus for the orientation of the tobacco stem.