PROBLEM TO BE SOLVED: To minimize the potential difference between the outer side and inner side of a wall surface of a resin container 2, in the sterilization of the resin container 2 by irradiation with electron beams.SOLUTION: A first sterilization wheel 8 carries the resin container 2 to a first electron beam irradiation area A in front of a first electron beam radiation device 12, and a second sterilization wheel 14 carries the container 2 to a second electron beam irradiation area B in front of a second electron beam radiation device 16 on the downstream side. The first electron beam radiation device 12 radiates electron beams at an accelerating voltage of a magnitude such that electrons penetrate the wall surface of the container 2 (e.g., 300 kV). The second electron beam radiation device 16 radiates electron beams at an accelerating voltage of a magnitude such that electrons do not penetrate the wall surface of the container 2 (e.g., 150 kV). Since electrons are accumulated on the inner surface side of the wall surface of the container 2 in the first irradiation, and electrons are accumulated on the outer surface side of the wall surface in the second irradiation, the potential difference between the inner and outer surfaces is minimized as the whole.
