Three MIL-100-type porous coordination polymers were synthesized using different types of anions and their water sorption properties were investigated. All of the compounds adsorbed huge amounts of water (0.6g g(-1)) at a moderate humidity (P/P-0 < 0.6), and one of the compounds showed the same adsorption property even after two thousand replicate water sorption tests. In addition, the pressure of water adsorption was found to be controlled by counter anions incorporated in the structure, which was attributed to the hydration energy of the anions.