We have developed an efficient inorganic adsorbent for carbon dioxide. This adsorbent is porous material made of hydroxyl aluminum silicate. This material can be synthesized easily from cheap raw materials. As the material can be produced in a large scale, low cost production would be possible. The amount of adsorbed carbon dioxide on this material is more than 10 wt% when the pressure of carbon dioxide is raised from 100 kPa (atmospheric pressure) to 900 kPa. This value is about two times larger than the amount of carbon dioxide adsorbed on zeolite 13X, which is now used for a carbon dioxide capture system. If the pressure swing adsorption (PSA) system can be operated above atmospheric pressure by using this material, the PSA system can collect carbon dioxide with low cost compared with the present system.