The present invention provides a silver based inorganic antibacterial agent excellent in heat resistance and chemical resistance, lowered in resin coloring and excellent in processability. The present invention has been completed by finding out that problems can be solved by a silver ion-containing zirconium phosphate represented by the following general formula (1) which is produced by a wet synthesis under specific production conditions.AgaNabHc(H3O)dZreHff(PO4)3.nH2O (1)wherein, in the formula (1), a, b, c, d, e and f are positive numbers satisfying 1.75<；(e+f)<；2.25 and a+b+c+d+4(e+f)=9； and n is not more than 2.
