A fluidized bed apparatus for batch-by-batch or continuous process control is provided that allows the processes in the fluidization region to be influenced as desired, especially in terms of material movement and dwell time. The fluidized bed apparatus is formed from at least two processing regions and the processing regions are connected to each other by overflow channels. The first processing region is provided with a solids inlet and the last processing region is provided with a solids outlet. For influencing the dwell time, the material to be treated is supplied to at least two processing regions one after the other and flows through these regions, wherein the material transport direction is a cross flow relative to the flow of the fluidization means.