A device for filling an extruder, which can optionally be an external extruder, with pretreated thermoplastic plastics material, in particular PET, has at least one evacuatable container (1) in which moving, in particular rotating, tools (7) are provided for pretreatment of the material. This pretreatment comprises drying and, optionally, crystallisation. Each container (1) has a discharge opening (18) for the flowable material (12), which discharge opening (18), with respect to the material, is fluidically connected to the filling opening (35) of the extruder (36). The device preferably has only a single container stage, the outlet of which is fluidically connected to a coupling (69), which is connectable to the filling opening (35) of the extruder (36), via a transfer section (31) maintaining the flowable state of the material (12) pretreated in the container (1) (FIG. 1).