To provide a peracetic acid-containing bactericidal composition which is effective to harmful bacteria such as bacteria of the genus Paenibacillus or Bacillus cereus, forming spore and having strong resistance to peracetic acid/hydrogen peroxide formulation.

It is well known that sterilization is difficult with respect to Bacillus cereus which is a spore forming bacterium having high chemical resistance, even if a conventional peracetic acid formulation is used. It is found that a peracetic acid composition in which a hydrogen peroxide content ratio in a peracetic acid equilibrium composition is lowered shows a high sterilization effect to Bacillus cereus which is a spore forming bacterium or bacteria of the genus Paenibacillus, to thereby complete a peracetic acid bactericidal composition which is effective even in the case of short-time treatment.