Fluidization of ultrafine particles with primary diameter of 7 nm is experimentally studied in a centrifugal fluidized bed (CenFB). Ultrafine particles can be fluidized without significant agglomeration of particles under high G. No bubble formation was observed in the CenFB of ultrafine particles. The entrainment of particles is suppressed by controlling G, The experimental data of pressure drop in the CenFB of ultrafine particles is larger than the estimated value. This is due to the energy dissipation required to overcome large adhesion force between ultrafine particles.