The invention relates to a method for thermal sterilization in particular of a container filled with medical material or product, the method comprising a sterilization method step in which a thermal sterilization in particular is carried out of a container filled with medical material or product in the presence of a sterilization atmosphere, containing steam, at temperatures of at least 100° C. and at increased pressure, wherein the sterilization method step comprises at least a first method stage and a second method stage, following the first method stage, with first and second method stages being carried out at different pressures with respect to one another, the pressure in the second method stage being increased relative to the pressure in the first method stage.
