In the present study, the cylinder surface-to-liquid mass transfer coefficient was measured in three -phase fluidized beds of 82 mm O. D., with glass beads(average diameter; 2.2-5.2 mm) and alumina beads (average diameter; 0.75-3.0 mm) as fluidized particles, using the limiting current method. One of the cylinder electrodes used was vertically inserted along the centerline of the fluidized beds and the other was horizontally set in the transverse direction of the column cross section. The outside diameter of the two electrodes was commonly 20 mm. The effect of operating conditions such as liquid velocity, gas velocity and particle diameter on the mass transfer coefficient was investigated. Unified correlations were developed from the measured surface-to-liquid mass transfer coefficients for the liquid-solid and three-phase fluidized beds in terms of the modified Colburn j-factor, or in terms of the specific power group based on the energy dissipation rate per unit mass of liquid. The presence of an analogy was confirmed between the mass transfer and heat transfer through the liquid film on the cylinder surface.