To provide both a bactericidal composition (for a food packaging material) capable of carrying out stable sterilization with peracetic acid at a substantially low concentration without changing sterilization conditions, apparatuses, equipment, etc., in any cases and a method for sterilization using the bactericidal composition.

This bactericidal composition can be used for sterilization, etc., of the food packaging material such as a packaging material made of polyethylene terephthalate. The method for sterilization uses the bactericidal composition. The bactericidal composition for the food packaging material comprises the following ingredients (1) and (2). (1) an aqueous solution containing the peracetic acid, hydrogen peroxide and acetic acid and (2) a bactericidal activity improver for the peracetic acid composed of one or more kinds of compounds selected from the group consisting of esters obtained from a 2-8C fatty acid and a 2-8C aliphatic alcohol, the 2-8C aliphatic alcohol and an aliphatic alcohol having a benzene ring.