A radioactive material adsorbent having large adsorption capacity is provided. The radioactive material adsorbent contains a titanate represented by a chemical formula M 2 Ti 2 O 5 (M: univalent cation). The M 2 Ti 2 O 5 has a large cation exchange capacity, exhibits thermal stability, exhibits excellent chemical resistance to acids, alkalis, and the like and, therefore is suitable for an adsorbent for a water treatment. The mechanical strength is improved by adding a binder to this titanate and performing forming and firing, so that pulverization due to vibration, impact, and the like applied during transportation and the like, and falling off of primary particles at the time of putting into water can be reduced.
