It is aimed to prevent electrical charging inside a resin material as well as a surface of a resin vessel at a time of sterilizing the resin vessel by being irradiated with electron beam. A bottle support unit is mounted to a lower end portion of a cylindrical rotating shaft rotatably supported by a rotating wheel. The bottle support unit includes a pair of griper members by which a mouth portion of a bottle is gripped. The bottle rotated and conveyed in a state supported by the bottle support unit is irradiated with the electron beam from an electron beam irradiator to thereby sterilize the bottle. A ground electrode is disposed to be capable of being inserted into the interior of the resin vessel through a mouth portion thereof, and the interior of the resin vessel is irradiated with the electron beam in a state of the ground electrode being inserted into the resin vessel. Since extra electrons or ions generated by the irradiation to the resin vessel with the electron beam flow outside, the charge amount of the resin vessel is alleviated.
