A self-propelled forage harvester is provided having a frame, a chopping drum, an accelerator arranged downstream of the chopping drum and a channel between the chopping drum and the accelerator. The channel has a section in which a conditioning unit or a hollow shell can be selectively inserted. The conditioning unit and the hollow shell are jointly supported on a pivot arm pivotable by way of a displacement drive about a pivot axis running horizontally and transverse to the forward direction. The conditioning unit is mounted on the pivot arm rotatably about an axis parallel to the pivot axis. The conditioning unit cooperates with the frame by way of a positive guide, which has the effect that the conditioning unit rotates about the axis in the same direction as the pivot arm.
