PROBLEM TO BE SOLVED: To uniformly sterilize a bottle cap by few electron beam radiation units by stabilizing an attitude of a falling bottle cap.SOLUTION: When bottle caps C are sterilized by sequentially falling the bottle caps along a vertical sterilization passage 15e in such an attitude that a cap axis passing through a center of an opening surface Ci becomes generally horizontal, and applying electron beams thereto: in the sterilization passage 15e, a closed surface Co of a bottle cap C is sucked via a suction port 25 along a vertical direction by sucking an atmosphere gas and electron beams are applied to an opening surface Ci of the bottle cap C； and, in the sterilization passage, the opening surface of the bottle cap is sucked via a suction port along a vertical direction by sucking the atmospheric gas and electron beams are applied the closed surface of the bottle cap.【課題】落下するボトルキャップの姿勢を安定させることにより、少ない電子線照射装置でボトルキャップを均一に滅菌する。【解決手段】ボトルキャップＣを、開口面Ｃｉの中心を通るキャップ軸心が略水平となる姿勢で鉛直方向の滅菌通路１５ｅに沿って順次落下させて電子線を照射し滅菌するに際し、滅菌通路１５ｅで、ボトルキャップＣの閉塞面Ｃｏを、鉛直方向に沿う吸引口２５を介して雰囲気ガスを吸引するとともに、ボトルキャップＣの開口面Ｃｉに電子線を照射し、滅菌通路で、ボトルキャップの開口面を、鉛直方向に沿う吸引口を介して雰囲気ガスを吸引するとともに、ボトルキャップの閉塞面に電子線を照射する。【選択図】図５
