To obtain an adsorbent having excellent adsorbing capacity to Co or Mn ions even in an aq. soln. wherein other cation such as alkali metal ions coexist.

In a granular material containing an adsorbent for Co or Mn ions represented by formula (1) HxM12-xM2(PO4)2.nH2O (wherein M1 is at least one kind of a monovalent cation selected from Li, Na, K, Cs, Rb and NH4, M2 is at least one kind of a tetravalent metal ions selected from the group consisting of Zr, Ti and Sn, (x) is 0-1.8 and (n) is 0-8), that containing at least one kind of a binder selected from a hydrogel and a clay mineral and an adsorbent wherein M1 in the formula (I) is a monovalent cation other than NH4 is baked at 250-600°C to obtain the objective granular adsorbent for Co or Mn ions.