The invention is intended to metabolize acetic acid and to lower acetic acid concentration in a medium at the time of xylose assimilation and ethanol fermentation by a yeast strain having xylose-metabolizing ability. To this end, a recombinant yeast strain having xylose-metabolizing ability and comprising an acetaldehyde dehydrogenase gene introduced thereinto is cultured in a medium containing cellulose, cellulase, and xylose to perform ethanol fermentation.