To clarify of the adsorption behavior of arsenic ions in alkaline solutions, we conducted arsenic adsorption tests for conventional adsorbents (polymer resin adsorbents and inorganic ion-exchangers). For polymer resin adsorbent, the adsorbent with glucamine groups adsorbed trivalent arsenic ions via hydroxyl groups in glucamine, and the strong base ion-exchanger adsorbed pentavalent arsenic ions through anion exchange. For inorganic ion-exchangers, hydroxides and iron hydroxide oxides had high ability to adsorb trivalent and pentavalent arsenic ions, and the adsorbability of hydroxides and iron hydroxide oxides for trivalent arsenic ion was higher than that for pentavalent arsenic ion. In particular, cerium(IV) hydroxide was found to be an excellent adsorbent for trivalent and pentavalent arsenic ions in alkaline solutions.