Experiments using a drop tower were carried out to investigate the effects of de and ac electric fields on the behavior of a bubble in a dielectric Liquid under a microgravity environment. As a result, the motion of the bubble was strongly affected by electro-hydrodynamic (EHD) convection in the liquid induced by the de electric field, Bubble motion under the ac electric field was primarily exerted by the dielectrophoretic force acting on the bubble itself, These experimental results were also explained by numerical simulation.