Disclosed is a silver-based inorganic antimicrobial agent which exhibits superior heat resistance, chemical resistance, processability and long-lasting waterproofness.The present invention was completed based on the finding that the problems can be solved by a silver-based inorganic antimicrobial agent represented by the following Formula (1) containing zirconium pyrophosphate (ZrP2O7).AgaMbZrcHfd(PO4)3.nH2O (1)(In Formula (1), M is at least one ion selected from an alkali metal ion, an ammonium ion, a hydrogen ion and an oxonium ion, a, b, c and d are positive numbers satisfying 1.75<(c+d)<2.2 and a+b+4(c+d)=9, and n is 2 or less).
