This paper reports a novel distillation method in microchannels. For the gas-liquid separator in the evaporator, hydrophilic-hydrophobic patterned microchannel structure was utilized. In order to control condensation of the vapor, nanopillar structures having a capillary radius of 270 nm were fabricated after the separator. In the nanopillars, vapor pressure is lower than that at a flat liquid surface. An aqueous Solution of 9.0 wt % ethanol was used as a model sample, and concentration of the condensed liquid in the nanopillar was estimated as 19 wt %.