A technique to apply a fluidized bed of electrically conductive beads is proposed to improve the uniformity of the electric field intensity in microwave applicators, which is required for uniform heating of media. The principle of this effect lies in the dynamic control of random reflections of microwave due to the motion of the conductive beads in the bed. The electrically conductive beads were prepared by wrapping aluminum foil around styrene foam balls and cellophane tape above it. The diameter and density of the beads were 13 mm and 123 kg/m(3) respectively. The minimum fluidization velocity of the beads agreed with that predicted by to Wen-Yu equation when the distributor was a porous plate. However, fluidization of the beads took place at lower gas rate than the minimum fluidization velocity due to a jet flow from the small pores for the distributor of a perforate plate. The intensity in the applicator of a commercial microwave oven became the most uniform when the beads were fluidized with a uniform hold-up profile along the height of the bed placed in front of the applicator walls. The dynamic effect making the field uniform by fluidization was improved with increases in the area of apparent reflection by the fluidized bed and in the hold-up of beads, and was superior to a conventional stirring blade.