This experiment was attempted to improve ethanol productivity by immobilization of Kluyveromyces marxianus F043 using Jerusalem artichoke powder. Sucrose medium was used to determine optimum conditions for cell immobilization. The optimum conditions were alginate concentration of 2%, bead size of 2 ㎜, a particle input ratio of 30 : 100, cultivation period of 24 hours, and substrate concentration of 10%(w/v). The immobilized cells produced the high concentrations of ethanol at pH 4.5∼6.5 and 30∼45℃, broader ranges of pH and temperatures than those of free cells. Under optimum conditions the immobilized cells showed ethanol concentration of 46.4 g/L and productivity of 1.93 g/L.h. The microphotograph using a two phase contrast microscope showed that immobilized cells cultivated under the optimum conditions were densely populated toward the surface area of beads.