Separation performance of water from various alcohol-water mixtures by pervaporation was examined using a polyion complex membrane. The alcohols used in this study were ethanol, 1-propanol, 2-propanol and 1-butanol. Both permeate fluxes of water and alcohols increased with increasing mole fraction of water in the feed solution. The values of permeate fluxes of water were almost the same for all alcohols tested, while those of alcohols decreased with increasing the number of carbon in the alcohol molecule. The solubilities of water and alcohols to the membrane were also examined by sorption experiment. The permeate fluxes of water and alcohols were analyzed on the basis of the solution-diffusion model considering the swelling of membrane caused by water. Permeate fluxes of water and alcohols were significantly affected by the degree of membrane swelling. Both solubility and diffusibility of water were larger than those of alcohols. Solubility and diffusibility of alcohols were reduced as the number of carbon in alcohol molecule increased.