Microcapsules of super absorbent polymer were synthesized by (W/O/W) emulsion and in-situ polymerization method and, vapor adsorption properties of microcapsules prepared under various conditions were investigated. The microcapsules prepared by adding salt to the outer aqueous phase and by miniaturization of the inner aqueous droplets showed stronger hygroscopicity than commercial silica gel. The supply of sodium ions was found to increase the hygroscopicity. Furthermore, the microcapsules could be used repeatedly, and their regeneration required little energy.