Disclosed is an antimicrobial composition comprising an antimicrobial activity enhancing agent for lactoferrin which contains ribonuclease-4 and lactoferrin, wherein the mass ratio of the ribonuclease-4 to the lactoferrin is 1/80 or more and 1/31.25 or less. Also disclosed is an antimicrobial composition comprising an antimicrobial activity enhancing agent for a lactoferrin hydrolysate which contains ribonuclease-4 and a lactoferrin hydrolysate, wherein the mass ratio of the ribonuclease-4 to the lactoferrin hydrolysate is 1/80 or more and 2/1 or less.
