The working bodies of agricultural implements should minimize resistance to movement. The shape of a curved tooth, which is fixed between two cylindrical disks, has been considered in this paper. Several such sections on the shaft form a drum similar to a harrow roller or a needle harrow. When rolling, the tooth sinks into the soil, followed by its loosening. The task was to find such a shape of the tooth, which at the first stage of immersion in the soil would slide over it as much as possible with minimal deformation, and at the second stage would balance it and turn it over. The object of the study is a drum-type working body. The work of a straight tooth with its transformation into a curved tooth was analyzed. As a result of such an analysis and subsequent search, a rational shape of a drum-type tillage working body was obtained for the purpose of reducing resistance when it is buried in the soil. The involute of a circle turned out to be such a curve. A tooth in the form of an involute of a circle has a peculiarity: at the moment of contact of the tooth with the ground, the absolute velocity vector is directed perpendicular to it. The result is explained by the fact that as the disks roll, the tooth sinks into the soil, and the point of entry remains unchanged, and the tooth itself slides practically along itself, especially in the upper layers of the soil. In known working bodies, their curvilinear form was selected experimentally. The proposed shape of the working body was obtained analytically. To reduce the resistance of the teeth entering the soil, the ratio of the tillage depth to the radius of the drum is important. The immersion of the blade to the full depth should correspond to a 30° rotation of the drum. After diving to the maximum depth, it begins to weigh the soil to the surface or loosen it. The field of application of such a tooth shape can be the improvement of the working bodies of tillage implements