Effects of the amounts of dirty materials and the numbers of microorganisms adhering to antimicrobial socks treated with modified metal ions (Cu2+ or Zn2+) were investigated. Correlation coefficient values between the dirty materials (ammonium nitrogen, Cl-, KMnO4 consuming substances, and total organic materials) and the bacterial numbers on control socks were respectively 0.898, 0.892, 0.939, and 0.921, suggesting a high correlation. In the meantime, those of antimicrobial socks were 0.572, 0.680, 0.491 and 0.559, respectively. Low values were also found in the fungal numbers. These results suggest that the antimicrobial socks treated with metal salts would contribute to decreasing the bacterial numbers adhering to them.