It is intended to provide a sterilization method for heat- resistant bacterial spores, with which an effective sterilization effect is attained under heating conditions milder than conventional conditions, and which hardly affects the quality of an object to be sterilized. The sterilization method includes performing a first heat treatment step having the main object of damaging spores and then performing a second heat treatment step having the main object of inactivating the damaged spores and being performed at a temperature lower than that of the first heat treatment step.
