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. 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.
