The drive device (1) is intended for a machine for the plasticization and injection of synthetic material. It comprises a main drive (2) drivable in a first and a second direction of rotation and having a hollow shaft (6) rotatable about an axis of rotation (4). An axially bipartite inner reception region (7) having a first part region (8) and a second part region (9) is formed by the hollow shaft (6). Rotation transmission means (10, 14), arranged at least partially in the first part region (8), are provided for the transmission of a rotational movement of the hollow shaft (6) solely in a first direction of rotation to an extruder worm (16) rotatable about the axis of rotation (4). Conversion means (12, 19, 20), arranged at least partially in the second part region (9), are provided for the transmission of a rotational movement of the hollow shaft (6) in the first and a second direction of rotation to a supporting shaft (11) rotatable about the axis of rotation (4) and displaceable axially in both directions and for the conversion of the transmitted rotational movement into an axial movement of the supporting shaft (11).